You can spin up your own mattermost server as well if you need something more modern. Good luck getting people to use it though, it likely won't have the buzz to use it.
Irc is fine too but good luck getting people to learn commands like /join #channel
This is the problem conservatives now have with everything.
They can't use the mainstream services, because they've been deplatformed.
They can't use alternate services, because they're different and require work to get users. Even getting users to enter a different url in their browser is work.
I was assuming OP already had a group of people he wanted to chat with, who cared about security and ban-proofing more than ease of use.
Anything where you set up your own server. For example, IRC chat.
Anything where a 3rd party controls the server like Discord or Slack or Twitter or Facebook is out straight away.
You can spin up your own mattermost server as well if you need something more modern. Good luck getting people to use it though, it likely won't have the buzz to use it.
Irc is fine too but good luck getting people to learn commands like /join #channel
This is the problem conservatives now have with everything.
They can't use the mainstream services, because they've been deplatformed.
They can't use alternate services, because they're different and require work to get users. Even getting users to enter a different url in their browser is work.
I was assuming OP already had a group of people he wanted to chat with, who cared about security and ban-proofing more than ease of use.