It’s not the expectation, it’s the reputation of the project. If a project does dumb stuff like taking down existing documentation, that reflects poorly on the project. It shows poor judgement and unreliability.

I don’t require them to be smart and professional, but they should be or will lose users. Thanks to OSS, I can just fork. But being OSS doesn’t mean you can suck and be random and still stay useful to people.

Of course if it’s your project, you’re free to do whatever you would like.