Over the weekend, former New York City mayor Michael Bloomberg delivered the University of Michigan’s spring commencement address, lecturing students on how it’s weak and wrong to demand “safe spaces.”

“The fact that some university boards and administrations now bow to pressure and shield students from these ideas through ‘safe spaces,’ ‘code words’ and ‘trigger warnings’ is, in my view, a terrible mistake,” Bloomberg, who travels everywhere with armed ex-police officers and conceals his private plane routes from aviation web sites, said.

“The whole purpose of college is to learn how to deal with difficult situations—not run away from them,” he continued. “A microaggression is exactly that: micro. And one of the most dangerous places on a college campus is a safe space, because it creates the false impression that we can insulate ourselves from those who hold different views,” the billionaire media mogul, who lives in a compound in a gated community in Bermuda, said.

“As durable as the American system of government has been, democracy is fragile—and demagogues are always lurking,” he said, before alluding to the candidacies of both Donald Trump and Bernie Sanders. “Stopping them starts with placing a premium on open minds, voting, and demanding that politicians offer practical solutions, not scapegoats or pie-in-the-sky promises.”

Earlier this year, Bloomberg considered running for president, but ultimately decided against it.