Well... Every app is doing that ;) Ah wait... There are some msg-apps that don't like Tox, Quiet, Briar, Bitchat.

Yep. But Telegram storing all of your group chat messages and having no end to end encryption by default is expected behavior, not your actions also being sent to some random C2 server from an unknown individual. Even nonprivate instant messengers wouldn't dare stoop so low!

Simplex, conversations connect to your server, molly...

I don't get those preaching freedom and using telegram and Twitter, makes no sense.

Yeah. SimpleX and Session are different in that way that you use your own relays or nodes.