A few months after I got off the airplane 39 years ago in San Francisco as a new emigre from South Africa, I learned a lesson about the local Jewish community that I will never forget.

I wrote my very first letter to the editor, which was published in Jewish Bulletin of Northern California, as J. was known then. My letter criticized an op-ed, written by the late Earl Raab, that drew an analogy between the apartheid government in South Africa, which I had just abandoned, and the Soviet Union of the 1970s. I believed then, as I do now, after the benefit of four decades of history, that I was right and Raab was wrong.

A prominent, and now deceased, member of Congregation Emanu-El in San Francisco called me in response to my letter, and in a tone exhibiting impatient annoyance, scolded me for defending the discriminatory South African system. The point of my letter was not to defend apartheid, but to explain that things aren’t always as they seem from the outside. My critic claimed that her views represented those of a majority of her congregation.

There are parallels one could draw between the two repressive systems, but they were so far apart in fundamental ways that the comparison simply didn’t hold water.

These days, people try the same trick with Israel, labeling it an apartheid-like system and shouting down speakers who say otherwise. They are also wrong, for different reasons.

An organized protest and an op-ed in J. against Emanu-El hosting New York Times columnist Bret Stephens as a guest speaker on May 25 reminded me of something I first heard from the late Rabbi Norman Bernhard of Johannesburg: “Sometimes people are so open-minded their brains fall out.” He happened to be an active critic of apartheid, but was prescient enough to understand that there needed to be some sort of balance even when opposing an oppressive system.

One need only look at the current abuse of freedom of speech occurring on U.S. college campuses to know how much trouble we’re in. Sadly, much of the acrimony is directed at Jewish students who are pro-Israel. Other Jewish students are in the baying mob.

I remember well the dark days of the South African academic freedom protests in the early 1970s, when I was a student at the University of the Witwatersrand. At that time, white students who wanted students of other races to be educated together with them were chased and hounded by truckloads of baton-wielding police, thrown into vans and taken away.

After seeing the violence committed by U.S. students who successfully muffle speakers that disagree with them, it pains me to see how right Rabbi Bernhard was, and how the hunted have become the hunters. Don’t they know that education necessitates allowing everyone to express their views (short of “fighting words”) in any public forum, without rude interruption? Don’t they know that their tactics will ultimately backfire and degrade the very freedoms they think they are promoting? Apparently not.

Particularly with reference to speakers who are pro-Israel, we see widespread anarchy on our university campuses. This must stop, or it will simply lead to greater violence. It is time for Jewish students, in particular, to refrain from drinking the Kool-Aid of some of their leftist colleagues before it chokes them.

I happen to be well acquainted with violence, but I never encourage its use as a first option. My almost 50 years of karate training started in South Africa, where personal injury lawyers were scarce, and sympathy for receiving a beating was unusual. To put it simply, I learned firsthand that violence begets violence — it’s not just a trite expression. But when it’s the only option, I also learned it’s better to be on the winning side.

It’s particularly shocking that there is a growing element within the American Jewish community that believes that violent protest against Israel on U.S. campuses, and elsewhere, is not only a right but a privilege. My advice to them is “be careful what you wish for.” Remember, too, that Israelis have civil rights just like you do.

Regardless of how right the left thinks it is, it is never acceptable to shut down speakers who promote the existence of the Jewish state. No country or system of government is perfect enough to withstand criticism, let alone Israel. But when freedom of speech in the U.S. is degraded within the Jewish community, of all places, I know instinctively that we’re in trouble. It looks increasingly like we may have to fight our way out of it, one way or another.

The right to disagree is an inherent Jewish value. It’s always better to avoid physical confrontation. If you can’t, it’s a tragedy when it’s your only choice, and even worse if you don’t know how to land a knockout blow to defend your own people.