Heres the thing, this is what huamns are. A shithead may be a shithead to one but a golden god to another. A truly open forum will reflect that. Moderation effectively splits different views and both can thrive without interaction with one another (echo chambers). I personally dont mind extremist views because it reminds me they exist and I am of sound mind to ignore them. However, I know not everyone is and I know the dangers of letting extremest views go unchallenged. I doubt technology can help us cover both fronts (open forum of ideas without echo chambers). Education can probably do a lot more. We need to be better humans, accepting of others and critical of ideas instead of people.
We started using more than one device and web accessed mail became the norm. POP3 still exists and you can use mail clients and delete everything off the server. Come to think of it, maybe we can then use syncthing to sync the mail across all other devices? Maybe?