Banishment is just enforcement of boundaries. It gets rid of a problematic person in a specific space where their behavior is not tolerated. It's about the community, not the banished. Once the troublemaker is gone, that's the end of it. Everyone goes back to their normal activities.
Cancel culture consists of people going out of their way to get a person banned everywhere else and even fired by their employers. People launch entire campaigns against the problematic person and make a concerted effort to ruin their life. Not that different from the Kiwi Farms.
Assertiveness and aggression.
What I'm talking about is the practice of following people around for using AI, rooting around for evidence that a project doesn't fully ban AI, etc. and publicly shaming them, harassing them, attacking them. People who do this don't accept neutrality or even mere skepticism, they demand full unconditional bans or else they make themselves a huge nuisance and try to harm you. That's cancel culture, plain and simple.