If an entity pays to advertise on a website, they'll usually be accomodated.
BTW, I have not seen any political ads on these forums. The ads that I see are typically related to recent web searches that I've done. Since I've been searching for airline flights, I've seen a few of those airline ads. I was researching rowing machines several months ago and started seeing ads for exercise equipment shortly thereafter.
Therefore, I suspect that some of the ads are automatically generated based on one's recent world wide web searching activities.