Not every service with user-generated content need to try to cater to maximum freedom of expression, so it first of all doesn't apply to any service with user-generated content.

Secondly, my point is that if you do have a service that is trying to optimize for freedom of expression, mixing in needing to earn money on top of that, is bound to leave you almost penny-less, as advertisers don't like an environment like that and people needing to be anonymous aren't as happy to donate.