Sorry for poor english.
If anyone wanted to discuss politics and operation with peers in similar situations than they are, while living in a heavily monitored and repressing country. What website / irc / whatever, should their refer to ?
I’m not asking “how to OPsec”, I’m asking “place to discuss when you have good enough OPsec”.
I think the biggest challenge to what you are asking is how to keep it safe when it turns out openly disclosed. Once you turn it public and easy to find the oppressing can target you. If you are looking for online groups maybe try tools that at least offer end-to-end encryption. Simple X groups or maybe now even Discord (not sure about this one but you may it works for your threat model). Matrix/Element can potentially be ok as well.
One tricky part is when you direct to the niche apps/services, you will more likely to stand out. If you use WhatsApp, it may not catch attention. But when you start to use things such as Signal, Simplex, Tor, then it will catch the attention of your authorities.
Edit: You should also divide the groups if it’s above certain number. So if one is compromised, that won’t affect other.
Definitely not irc. Some sort of simplex chat group or possibly a .onion site would be best.
That’s an interesting idea. Just keep in mind, in a large enough group, one people is bound to leave WA’s backups to Google Drive unencrypted, which means some governments will have overnight access to the whole group’s conversation. So in case the repressive country OP lives in is the US or one of its allies, it actually becomes a terrible idea.
Yeah, I know it. They can also seize directly the phone itself in authoritarian regimes. Besides, hiding/blending in the crowd will mostly work when you or your account are not discovered/targeted by the government. If you are on the radar, they can simply hack your phone with pegasus or similar spyware. That totally depends on the threat model. Btw, I was not suggesting the use of WhatsApp, but gave it as an example. 
This is bad advice to use whatsapp as a political dissident.
Whatsapp has pen registers that update every 15 minutes. Meaning they know exactly who you talk to. There is also the issue of backups that was posted.
Its makes no sense to use a non-privacy focused messaging app to ‘stay off the radar’ when that app shares so much data you are automatically on the radar.
I would suggest using Matrix logged in from the web browser, launched from disposable virtual machines. Or using proton with disappearing messages only sent to PM emails to enforce E2EE and again only from disposable VMs.
SimpleX could be a another good option.
The disposable VM is to prevent forensic searches of the device revealing participation in dissident activities. Disposable VMs also can provide protection against Pegasus since its not a smart phone (most commonly targeted), but also since it would most likely limit the persistence of any exploit. Plus the exploit most likely won’t be able to escape virtualization to infect the main device.
Depending on everyone’s tech skills manual PGP could be an option, but it requires careful handling of keys. I’ve seen advanced groups that used PGP + TOR only.
please re-read my post.
Providing you dont share any personal information and use a separate profile, Github might be a good option. I know that it’s used in China as it isn’t blocked