Back in the 90s early 00s the internet made us mesh together because each one of us there was a specific person. We had forum signatures and every single post was clearly made by a person, for a person.
Then social media took over and relegated every single person into a tiny unidentifiable avatar next to a non-prominent name, not unlike NPCs in CRPGs.
In turn this has been exploited by the powers that be to ensure the social glue gets even weaker: a society barely held together won't revolt. There's only one thing left to do: productivity, productivity, productivity.
The political opponent is no longer a person. Just a nameless, faceless NPC (personifying everything that's wrong) spawned there to be defeated and collect their social loot tokens.
But I might just be an old fart rambling about the good, old days.
You’re going to keep running into a wall thinking of discord like a forum replacement; It’s designed to be an IRC replacement.
The invitation system intentionally creates some privacy so you can build a sense of enclosed community around them, and so you have some control over who sees what. Not having your conversations on full automatic blast to the public is a feature.
The invitation system gives a false sense of privacy. There are bots that crawl publicly posted invites, public IRC channels, etc. Eventually people will understand that IRC and discord are public in the same way we understand usenet to have been public