I'm a member of plenty of discussion groups that run on a VBulletin board or something where you can register and start posting. Why doesn't the local university feminist organization do that, why do I have to give give up my private info to Zuckerberg et al just to be part of it?

Maybe I'm weird but my larger social groups are usually focused on specific things and I'm happy to interact with them in a forum designed specifically for that purpose, not owned by a huge information-sucking company.

In fact, I find the requirement to be a member of Facebook as a condition of productively working with that feminist org to be really exclusionary.