That has nothing to do with the current political climate. Advertisers were reluctant to advertise against anything not perfectly anodyne 20 years ago. This was a perennial problem for us at early community site bianca.com.
The specific things that people complain about has changed, sure. At the time the US right was much better at the game, insisting that everything be "family friendly". And at the time, anything GLBTQ related was seen as "not family friendly".
That has changed, though. For example, support for gay marriage has flipped, going from a minority position to a majority one:
http://news.gallup.com/poll/210566/support-gay-marriage-edge...
That's what makes YouTube's behavior here particularly notable. If, say, relationship advice is monetizable but GLBTQ relationship advice isn't, then that feels like going back to the dark ages.