There seems to be a lot of line-drawing about 'cancel culture' these days. My own view is relatively simple: don't talk about private people (meaning, more private than yourself) in public. Don't talk about kids. Don't rehash the past. Don't be offended on someone else's behalf. If the concern is about ideas, be respectful. If it's about conduct, model good conduct (it's okay to make jokes though, that's how we learn conduct rules). When you say your piece, don't ask for someone to get fired. Don't conditionally boycott based on that stuff – boycotting ought not be transitive. Just because you don't like something, doesn't mean you should stop liking someone who doesn't care.
That's it. Obviously, people do bad stuff, and I think we should say so. I won't always be convinced you're right, and that's fine, I'm only sometimes persuasive myself. I will say that, if the issue is someone's thoughts, disagree with them, but don't admonish them unless it's an issue with behavior. That seems simple enough. Speech is a behavior – if people are rude, that's not good (and deserves a quite mild admonition). But if they can/have phrased things reasonably and charitably, just disagree. Consider:
But no matter your opinion on how society should treat these speech acts, that’s what’s under discussion: not “is free speech good?” but “should X be a socially acceptable expression?”
I think my instinct here is that, I will allocate my disagreement in proportion to the difference in opinion, and my social opprobrium in proportion to violations of etiquette. Almost all opinions can be made polite if phrased kindly (I've attempted to steer friends away from casually repeating conspiracy theories suggesting specific living individuals are murderers – not admonishing them truly, but just like, I wouldn't say that without high quality evidence, they're real people with friends – which I think tests the bounds of being polite as much as any opinion truly could).
Yes, I know, this means I can 'only intensely disagree' with polite and respectful communists and neo-Nazis, and they aren't silenced to your liking. Suffice it to say, I spend a lot of time disagreeing with them, and I don't totally understand what you want me to admonish them for – they already know I strongly disagree with them, and we're hashing it out respectfully (in this hypothetical you've imagined – while I've done this with communists, the other one is simply too rare for me to have actually bumped into).
It's not a perfect code of conduct, but it's the one I'm thinking about right now. Feel free to correct me if you think I've stepped out of sync with it.