Can this board be inane at times? Yeah, but it's usually self contained and doesn't pose much danger to society at large. For that /pol/ takes the cake as it's a board full of alt right and reactionary losers.
Second would be, surprisingly enough, /his/ mostly because it overlaps with what I do. That's another board full of nationalists and other far right groups but this time hiding their sinister beliefs under the guise of history and being less obvious than /pol/. These lads strike me as the type to attack Muslim women for covering themselves but turn around and jerk themselves off to classical Athens. A society that under her thin veneer of marble and "freedom" was a society of extreme misogyny, women, foreigners, and slaves were disenfranchised and couldn't own property, and the Athenians built their empire by bullying and destroying communities. Oh, and they also held trials in earnest for inanimate objects, so much for the wise Athenians. Appropriation of history by far right groups is a real danger as well. And because of that this board can never ever be as bad as those two.