Duterte: Hitler killed millions of Jews, I will kill millions of drug addicts

[Suburbia]

There ought to be limits to free speech. At the very least, saying certain things should make someone ineligible to run for political office.

No, there shouldn't. If you don't like what he said, don't listen to it. You can't limit free speech. You don't like free speech, move to a totalitarian state like North Korea. You can't shut down people just because you disagree with them.