Like other governments across the Middle East, Egypt has not been shy about its position on the Israeli-Palestinian conflict. Its denunciations of Israel over the war in Gaza are loud and constant. State media outlets broadcast images of long lines of aid trucks waiting to cross from Egypt into Gaza, spotlighting Egypt’s role as the sole conduit for most of the limited aid entering the besieged territory.

Earlier this month, however, when hundreds of people gathered in downtown Cairo to demonstrate in solidarity with Gaza, Egyptian security officers swooped in, arresting 14 protesters, according to their lawyer. Back in October, the government had organized pro-Palestinian rallies of its own. Yet at those, too, it detained dozens of people after protesters chanted slogans critical of the government. More than 50 of them remain behind bars, their lawyers say.

It was a pattern that has repeated itself around the region since Israel, responding to an attack by Hamas, began a six-month war in Gaza: Arab citizens’ grief and fury over Gaza’s plight running headlong into official repression when that outrage takes aim at their own leaders. In some countries, even public display of pro-Palestinian sentiment is enough to risk arrest.

Out of step with their people on matters of economic opportunity and political freedoms, some governments in the Arab world have long faced added discontent over their ties with Israel and its chief backer, the United States. Now the Gaza war — and what many Arabs see as their own governments’ complicity — has driven an old wedge between rulers and the ruled with new force.

Morocco is prosecuting dozens of people arrested at pro-Palestinian protests or detained for social media posts criticizing the kingdom’s rapprochement with Israel. In Saudi Arabia, which is pursuing a normalization deal with Israel, and the United Arab Emirates, which has already struck one, the authorities have displayed such hypersensitivity to any hint of opposition that many people are too frightened to speak on the issue.

And Jordan’s government, caught between its majority-Palestinian population and its close cooperation with Israel and the United States, has arrested at least 1,500 people since early October, according to Amnesty International. That includes about 500 in March, when huge protests were held outside the Israeli Embassy in Amman.

Afterward, the president of the Jordanian Senate, Faisal al-Fayez, said that his country “will not accept that demonstrations and protests turn into platforms for discord.”

Arab autocracies rarely tolerate dissent. But activism around the Palestinian cause is particularly thorny.

For decades, Arab activists have linked the struggle for justice for the Palestinians — a cause that unites Arabs of different political persuasions from Marrakesh to Baghdad — to the struggle for greater rights and freedoms at home. For them, Israel was an avatar of the authoritarian and colonialist forces that had thwarted their own societies’ growth.

“What’s happening to the Palestinian people clarifies the foundation of the problem for Arabs everywhere, that the problem is tyranny,” said Abdurrahman Sultan, a 36-year-old Kuwaiti who has participated in sit-ins in support of the Palestinian cause since the war began.

Kuwait initially tolerated some of the sit-ins. But for some Arab governments, the connection evokes peril. Palestinian flags were a common sight at the Arab Spring protests that swept the region in 2011. In Egypt, where since taking power in 2013 President Abdel Fattah el-Sisi has quelled protest and muffled most criticism, the authorities are ever mindful that activism can quickly boomerang against them.

“Today they’re out to protest for Palestine; tomorrow they might protest against him himself — the president,” said Nabeh Ganady, 30, a human rights lawyer who represents the 14 activists arrested at the April 3 protest in Cairo.

The message, said Mahienor El-Massry, a human rights lawyer who joined the demonstration, “is that people shouldn’t even dream that there exists any margin for freedoms or for democracy, and that you should never gain confidence and then move toward bigger demands.”

Ms. El-Massry was arrested along with 10 other protesters during a smaller solidarity protest outside United Nations offices in Cairo last Tuesday, according to Ahmed Douma, a well-known Egyptian activist. They were later released.

In interviews conducted around Egypt, Morocco and Persian Gulf countries — including Saudi Arabia, the United Arab Emirates, Bahrain, Oman and Kuwait — many citizens described the Israeli-Palestinian conflict in stark terms, viewing the Palestinian cause as a struggle for justice, Israel as a symbol of oppression and, in some cases, their rulers’ dealings with Israel as morally bankrupt.

Coming after agreements by Bahrain, Morocco and the United Arab Emirates to normalize ties with Israel, along with Saudi steps toward following suit, the war has galvanized outrage in those countries toward not only Israel but also Arab leaders willing to work with it.

“If you’re willing to sell that, and sell those people out — sell yourself out — what’s next? What else is for sale?” said Salem, an Emirati in his 20s who asked to be identified by a middle name, given the Emirati authorities’ record of punishing dissent.

Governments that signed agreements with Israel have often described the decision as a step toward greater regional dialogue and interfaith tolerance. In February, the Emirati government said in a statement to The New York Times that keeping its diplomatic ties with Israel open was “important in difficult times.”

But because of hostility or, at best, indifference toward Israel in the broader Arab public, there is a “direct, necessary connection” between authoritarianism and the signing of such agreements, said Marc Lynch, a political science professor focused on the Middle East at George Washington University.

The fact that some gulf Arab states have used Israeli surveillance tools to monitor critics only cements that impression.

“If people had any space to democratically elect or express, they wouldn’t choose to normalize with Israel,” said Maryam AlHajri, a Qatari sociologist and anti-normalization activist.

Many Arab governments have tried to tame or harness popular anger with heated rhetoric condemning Israel over the war. Yet they see too many practical benefits to ties with Israel to renege on peace deals, analysts said.

Egypt, the first Arab country to make peace with Israel, has developed a close security partnership with its neighbor over years of jointly combating militancy in northern Sinai. Egypt and Israel have also worked together to blockade Gaza to contain Hamas, whose brand of militant political Islamism Egypt considers a threat. And Egypt needs Israel’s cooperation to prevent a huge influx of Palestinian refugees from Gaza.

Gulf monarchies, including Saudi Arabia and the Emirates, which have for years faced attacks by Iran-backed groups, have long maintained back-channel security connections with Israel, which sees Iran as its greatest threat. That enemy-of-my-enemy arrangement paved the way for normalization talks later on, and critiques of those initiatives are rare since many gulf monarchies effectively ban all forms of protest and political organizing.

H.A. Hellyer, a Middle East security expert at the Carnegie Endowment for International Peace, said governments were “trying to thread a line between that anger, which I think is very genuinely felt, across all sectors of Arab societies, and what those states interpret as their national security considerations.”

In the past, some of the region’s leaders permitted their frustrated populations to blow off steam with pro-Palestinian and anti-Israel activism. But now that the suffering in Gaza implicates Arab governments in the eyes of many of their citizens, the chants tread on sensitive territory.

Some Egyptians have criticized their government for, among other things, allowing Israel any say over the delivery of desperately needed aid into Gaza through a border crossing in Egypt. And since October, Moroccans have gathered for large, near-daily solidarity demonstrations in about 40 cities that bring together leftists and Islamists, young and old, men and women.

Mostly, the authorities have left them alone. But a few protests have been repressed, according to rights groups and witnesses, and dozens of protesters have been arrested, including a group of 13 in the city of Sale and an activist named Abdul Rahman Zankad, who had criticized Morocco’s normalization agreement with Israel on Facebook.

Mr. Zankad was sentenced to five years in prison this month.

“People are arrested simply for voicing their opinions,” said Serroukh Mohammed, a lawyer in the port city of Tangier and a member of an Islamist political organization. Moroccans will continue to protest, he said, as long as their government defies popular sentiment to maintain ties with Israel.

Representatives for the governments of Egypt and Morocco did not respond to requests for comment.

For Arabs like Mr. Sultan, from Kuwait, the absence of popular support for relations with Israel means any normalization agreements are doomed to fail.

“To make peace, you need regimes and governments that represent their people, that are elected,” he said.

Aida Alami contributed reporting from Rabat, Morocco.