If you're an experienced activist, it won't be a surprise to you that Telegram became one of the primary communication networks for human rights activists all over the world. I guess ever since Whatsapp was bought by Facebook, people have been switching to Telegram. Even though it doesn't offer the privacy and security that apps like Wire offer, it's way easier to use and still offers a huge advantage over compromised social media. So in that sense it's certainly a step in the right direction.
Here are some Telegram chat groups that I recommend you to join if you're into human rights and activism. I'm only listing those that you can actually freely talk in, as hierarchies disgust me.
Irish Chat:
https://t.me/Irish_Chat
Operation Uprise:
https://t.me/operationuprisechat
/pol/
https://t.me/politically_incorrect_community
Revolution In The Streets:
https://t.me/revolutioninthestreetschat
We Are Change:
https://t.me/wearechangechat
World Wide Demonstration:
https://t.me/worldwidedemochat
Now, just a quick note: I don't consider Telegram a safe platform at all. Treat everything like you're in a public marketplace. Share only what you want the world to know and remember to always stay secure.