Note that reddit devs are trying hard to hide these controversial subreddits. You won't see them if you go to https://www.reddit.com/ for instance. That's partly why they introduced the "popular" meta-subreddit a while ago. Reddit is pretty advertiser friendly, hence famous people making AMAs to promote something, official or semi-official subreddits for some video games etc... If you want to see the controversial content you have to look for it, for the most part. I consider it very hypocritical of reddit admins to handle things that way but it seems to work decently for them so far.
Contrast that with something like https://voat.co/ for instance. At the moment I can see only one (1) post in the entire front page that's not alt-right politics. Special mention to the highly upvoted "If women have the right to terminate unwanted life because it's in their body, do we have the right to terminate unwanted illegals because they're inside our country?". I don't expect most advertisers will want to touch that with a one parsec pole.
Contrast that with something like https://voat.co/ for instance. At the moment I can see only one (1) post in the entire front page that's not alt-right politics. Special mention to the highly upvoted "If women have the right to terminate unwanted life because it's in their body, do we have the right to terminate unwanted illegals because they're inside our country?". I don't expect most advertisers will want to touch that with a one parsec pole.