Maybe a way to flag topics to hide similar ones from yourself would be helpful, but applying this more generally to the entire community doesn't sit well with me.
Agree. If topics and comments are going to be hidden because they're "political", there should be a way to view and upvote these if you want to "opt-in".
There is. Set "showdead" to "yes" in your profile. You can "vouch" for comments made by banned users.
That's what "hide" does for a submission, though you have to do that on per-submission basis.