I don't see where we disagree. Like voting for an intolerant political candidate, I'd consider donating to them to be use of force. It's no longer a matter of simple "intolerance" once that happens. At that point I've lifted a finger, so to speak, just as if I'd paid a thug to beat up some gays outside a bar.

Simply expressing verbal support for the candidate, on the other hand, wouldn't be an instance of the use of force.

The passage from Karl Popper you quoted contains the problematic language, "But we should claim the right to suppress (utterances of intolerance) if necessary even by force." That's where an arbitrary exercise of unequal power comes in. Unless Popper is claiming that an external source of morality exists to decide who's allowed to respond to speech with violence and who is not, he's on very shaky philosophical ground.