There is no should or shouldn’t, they’ve always had and been entitled to that choice. People who develop and host those platforms can make whatever choice they want.

ActivityPub/the Fediverse is only a protocol. If you philosophically disagree with how a platform makes use of that protocol, then you can (theoretically) just use another platform.

I’m surprised to hear that anyone would complain about this with C. Even the Wikipedia page about encapsulation cites C as a non-OOP language example.