Well, sure. But the point is that server administration isn't free and it still requires somebody to actually do the administration. Open source is great, but people have to eat, and getting fair compensation for your effort isn't an unreasonable ask.
Some people just want to do good things to others if they can. They get some donations and more importantly love and respect from the community. It's enough for them, at least as long as the project doesn't become very popular. Unfortunately many people now don't care about anything except money so they can't understand. And the problem with paid subscriptions is more about privacy I think