It's a private discord. They can do what they want.

That being said...

1) You don't have to agree with it.
2) You don't have to agree with their practices, which to me at least are shady. Especially the streamer situation I read in those posts.
3) You don't have to join that community, be a part of it, or interact with it in any way.
4) It's entirely valid to critique or point out bad practices all around. Example, how they handled their streamers. The harassment of the minor inside the discord. Etc.

From what I can see, that discord is doing a good job all on its own for destroying itself. Seeing how they treated their streamers, harassment of a minor, and the weird way they go about things is just... concerning, but that's their problem to deal with.

If some girls want a "safe space" away from us guys, have a ball. Absolutely nothing wrong with that premise. The purpose of the discord shouldn't be the 'issue', but the actions that occur from it should be.