Falsifiability was Popper’s demarcation of science, not his demarcation of tolerance (if he had one).

Note that he specifically says in that passage that he’s not advocating the suppression of all intolerant speech. Thus even if some speech were intolerant, that by itself would be insufficient for suppression.

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Misinformation is problematic to the extent that it endangers the open society’s very existence, and with it its ability to self-correct.

The problem as I see it is not one of punching Nazis but identifying Nazis. The people I see who are the loudest advocates of Nazi-punching tend to be the same people who reflexively use "Nazi" to refer to anyone they disagree with, no matter how inaccurate the label. The inevitable result is that non-Nazis get punched, then they start punching back.

> Nazis are not up for a debate about their ideas and so can be punched

Many leftist would meet this criteria just as strongly ala "My <x> is not up for debate." or other statements conflating ones existence with ones identity with the same result: No discussion (outside a select, tautological group of gatekeepers) allowed.