Known for his critical rationalism and vehement opposition to authoritarianism, Popper would probably be spinning in his grave if he knew that his essay is cited as a token every time someone is persecuted for posting the wrong kind of tweet.
I don’t think Popper would be so naive to just limit intolerance to physical violence (which is already ruled out by law, so why bother).
The intolerance is against anything intolerant that if given enough power will stamp out (violently) Democracy itself.
One just needs to look at Putin’s Russia to understand what he meant.
Popper was completely in favor of free speech, and a completely open society, with no censorship except in the cases of actual violence:
"he is known for his vigorous defence of liberal democracy and the principles of social criticism that he believed made a flourishing open society possible" [1]
It’s indeed tricky, but the sorting criteria is: once in power, would these people club me to death, or let go of power if they lost a free election?