Neither myself nor the author
I have no way of knowing that you are not the author, if you feel addressed and unfairly attacked, I apologize.
Firstly, why the hostility?
Because it's an extremely ignorant position. Literally. When you visit their website the information that it is an association and a community is BLASTED into your face.
If a user moves away from MSFT/github because they don't like them, I would very much expect that new user to do the bare minimum of investigating who this new thing is they trust with their code. And an association has official membership and of course those members get to vote on such things. That's how any club works. If the music club in school does a performance, the club decides what they're going to play, not the audience.
Can you really confidently claim that everything was communicated perfectly regarding this ban?
This is not a "I have a contract with this corporate entity and I am entitled to service, communication or compensation" situation.
This is a "I have half heartedly joined a club, didn't care for the club activities or opinions of the community and I am acting surprised and pissed that the club is doing club things." situation. Which is ridiculous and deserves ridicule and hostility.
But also, if this is a thing they have a problem with, self hosting is the perfect solution for the author.