Politics is combative by its very nature.
maintaining civil discussion on the matter is nigh impossible.
What the "ideal" political forum looks like is a place where people can talk about current events, provide insight and perspective, communicate differing viewpoints in a constructive way, issue corrections in the face of bad takes, and somehow not have it devolve into autists getting their panties in a bunch when they're told "no."
Optimistically: something kinda like this might be achieved with stricter "tone-policing." Allow debate. But issue warnings/bans, on a fairly arbitrary basis, when someone starts throwing a shitfit. Calling a retard a retard when they post something retarded is fine and should be encouraged. But if that's all someone is bringing to a discussion they probably shouldn't be participating at all. Ban threats of violence too, even if it's punctuated with "in minecraft." A community that constantly advocates for assassinating politicians, even in a *wink-wink/nudge-nudge" manner is going to be a lightning rod for unhinged retards that might actually do it.
In short: you'd need a comprehensive "broken windows" policy. If users see retard shit going unpunished, that tells them retard shit is okay. If they only see informative, insightful, and productive posts, they'll know that is what's expected of them.
Is this even possible in practice? definitely not with just one dude, especially if he isn't chained to his computer desk 24/7.