If you think like that, then why not just delete these boards, since they're not Bitcoin-related ? Except Games and rounds, where there is something to say, and even, I would personnaly keep it, the other sections all have something interesting.
I don't find the Politics & Off topic sections discussing anything interesting but wouldn't want these sections to be deleted as they must have been introduced so that members can contriubte something useful. Users chasing activity points and misusing these sections would stop to an extent if these sections don't add up any activity points.
Some people does only posts to these sections, or a big part of their posts. Let's take bryan.coleman exemple. Is he considered as spammy ? He post a lot, maybe exclusively, in the Politics & society section. I'm not an expert of this section (I think that I even never posted there), it seems that like Meta, you can't spam like people do in the Games and rounds section.
Also, if we deleted the activity points given there, we would end up with ghost places, with no one in, because they would feel as excluded, and their contributions there would not be recognised.