It's interesting to see the comments from people who supported Youtube/Twitter/FB/Patreon/Visa political censorship, but are suddenly against the porn censorship by the payment same systems. "Rules for thee, but not for me."
There are compelling alternatives for many of the platforms you mention; what was happening to OF amounted to a complete disqualification from infrastructure.
The number of users is important, and they have monopolies on the user base.
Learn about network effects.