I think the difference with simplex and oxchat is that while the members of the chat can share the information there is not a large central entity that can compromise the privacy of any group. Telegram has fantastic ux and features along with a great network effect but I'm happy that whatever is going on is creating enough disturbance for people to start trying out other options.
Discussion
It’s very easy to social engineer your way into being accepted by someone in a large group, and that gives you an “in.” I can understand it if the concern is a central entity being able to shut the group down, so I’m not saying looking at decentralized options is a bad thing. But any large group chat/channel might as well be a public forum from a privacy standpoint.