I like to think about these issues as "website moderation policies" because that's all it boils down to. Almost all sites have moderation and for good reason. Besides all the spam and trolls good moderation helps build a community. That's why we're all here, and also why I'm selective about what subreddits I join.

If a company is so powerful that their moderation policies are effectively censorship, then there is definitely a serious free speech concern. The solution is to break up the monopoly so that no one company is that powerful.