Because Sexplanations talks about sex, advertisers considers the show non-ideal inventory that they don’t want to associate with, so Sexplanations makes about ten times less per view than the average YouTube channel.
From Hank Green's Tumblr:
via edwardspoonhands.com/post/96179214694/tumblingdoe-a-screenshot-of-the-lifetime
So you can, but you are more likely to make less than others.
I'm not too familiar with the system, though my guess, but don't just take my word for it, would be that it's either per-video judgement basis (maybe they base it off tags/description/title?) and/or what the majority of the channel is about.Would they label all your content like this if you only did one video on a topic. Like say if you had 50 videos on other topics and one on sex-ed would they just not want to associate with you, or not want to associate with that one video?