This past week, we learned of yet another educator at the University of Michigan who has refused to give a Jewish student a promised letter of recommendation for an academic program in Israel because the instructor supported BDS.

But the good news is that we also found out that the first professor to discriminate against a student for wanting to study in Israel was disciplined by the school.

That’s encouraging because it shows that a major American academic institution is willing to stand up against anti-Israel bias. It’s equally important because as the two students at Michigan learned, the prime targets of BDS boycotts aren’t so much Israelis and Israeli institutions as they are American Jews.

Which is why the news about Israel preventing a Palestinian-American student from entering the country to study at the Hebrew University in Jerusalem is both ironic and infuriating.

The student who got held up at Ben-Gurion International Airport, Lara Alqasem, has already done more damage to Israel’s image than most pro-BDS activists. By managing to get herself detained—Strategic Affairs Minister Gilad Erdan insists that she was never arrested—Alqasem ignited a controversy that has been reported about around the globe and brought down a deluge of criticism on the Netanyahu government. But unlike most such instances in which Israel is falsely accused of discrimination or other bad conduct, there’s no escaping the fact that the Jewish state stands guilty here. Of course, the government’s offense isn’t a war crime but rather criminal stupidity.

The stupidity in question was the Knesset’s decision to pass a law last year that allows the government to ban anyone from entering the country if they are aligned with one of 20 groups singled out for support of BDS. Those who fall under this category are, like Alqasem, undeserving of much sympathy. BDS is a movement that doesn’t merely seek to change Israel’s security policies, adjust its borders and advocate for an independent Palestinian state. Its goal is Israel’s destruction.

Alqasem was reportedly the president of the University of Florida’s chapter of Students for Justice in Palestine. SJP is avowedly anti-Zionist and anti-Semitic. Its platform explicitly states that it wants to “end Israel’s occupation and colonization of all Arab lands.” Since it also endorses the “right of return” for the descendants of the 1948 Arab refugees, it considers all of Israel—and not just the West Bank—to be “occupied.” And just like the Palestinian terror movements it supports, wherever SJP’s members show up, acts of anti-Semitism, and even violence and intimidation aimed at Jews, follows.

Even worse, SJP is funded by the same people associated with the Holy Land Foundation, a Hamas front organization that was shut down by the U.S. Treasury Department more than 20 years ago.

Yet keeping someone like Alqasem out is still foolish.

While we don’t know her motivations, she wants to study at Hebrew University. That’s the sort of thing the professors at Michigan have tried to stop Jewish students from doing. Indeed, study at Hebrew U is antithetical to BDS, a movement that seeks to isolate Israeli academics and their schools. Moreover, Alqasem claimed when speaking in court last week that she didn’t support BDS, which makes sense if she wishes to study in Israel, though it’s hard to reconcile that with her active membership in a group whose entire purpose is to push for an economic (and academic) war on the Jewish state. The fact that, as Erdan claims, Alqasem erased her social-media accounts before coming to Israel raises suspicions about her intentions.

But while Israel, like every other country, has a right to determine who may cross its borders and to exclude those it deems to be threats, keeping BDS activists out winds up hurting the Jewish state. It also makes no sense since their presence there contradicts their very ideology.

If Alqasem is a genuine security threat, then she should be banned. But, like the others who have been turned away or hassled at the airport, she is merely an annoyance and not a terrorist.

The debate over whether Israel is justified to detain and deport supporters of BDS begs the question of who really suffers from these efforts.

For all of its publicity and bluster, the BDS movement has done little damage to Israel. Aside from efforts to pressure performing artists to stay away, it’s been a colossal flop. Israel was once an impoverished nation that struggled to deal with an Arab boycott in its first decades. But today, it has a First World economy that dwarfs that of any of its neighbors. The SJP’s puny efforts to ban Sabra-brand Hummus from school cafeterias are no threat to Israel’s mighty “Startup Nation” economy.

While SJP and BDS can’t hurt Israel, they do pose a genuine threat to American Jews. It is Jewish students who are singled out for opprobrium, and isolated and attacked on campuses by SJP activists with the aid of their anti-Zionist allies in radical pro-BDS groups like Jewish Voices for Peace. It can create an atmosphere in which it is difficult for Jews to publicly express their identity.

And that is precisely why Israel should, at least in this one instance, listen to Diaspora Jews when they tell them their anti-BDS law is counterproductive.

By keeping left-wing activists out of Israel, Erdan is handing Israel’s opponents an unearned propaganda victory since it bolsters their lies about Israel being an apartheid state, without doing anything to make Israel more secure. It makes it easier for groups like SJP to justify anti-Israel efforts and harder for Jews to stand up for it.

While many Jews recognize the impulse to keep unsavory characters out of their country, Israeli leaders need to realize that doing so is merely an act of resentment that makes their country look like a police state, rather than a vibrant and diverse democracy.

The best ways to fight BDS are efforts to punish those who discriminate against Israel and Jews as the campaigns to pass anti-BDS laws has proved. Israel should keep its borders open to American travelers and students who can witness for themselves what a democratic Jewish state looks like. It’s time to rescind Israel’s BDS law and refocus on what it can do to help, rather than hinder, Diaspora efforts to defeat it.

Jonathan S. Tobin is editor in chief of JNS — Jewish News Syndicate. Follow him on Twitter at: @jonathans_tobin.