@aral yes, that is one of the ways in which Twitter is not like most post offices.
It depends. What are the alternatives? Does one's continued use of a service really help the provider of that service?
I think way too many people are continuing to use Twitter/X right now, and if the people who don't have good reasons to keep using would stop, the most important reason for many of the people who do have a good reason for staying would cease to be.
@aral but let's say the post office is owned and operated by a nazi. That probably means there's not really an alternative. I wouldn't hold it against the people living in Nazi Germany to continue using the postal service, even if it was run by the Nazis.
Placing personal ads in Der Sturmer would be a different matter, and at the moment, Twitter/X is somewhere between those two.