If Google really wanted to make money --> They'd widen their range. Make an AdSense Adult Section. Make an option - Do you want this ad to display adult advertisements? For AdWords - Is this ad an adult advertisement? If you're Google then wake up and smell the coffee. If I am not mistaken, the adult industry makes up 60% + of the internet. And when you're the king of all kings and most people use your program to make money online already, I would definitely think that it'd be time to take advantage of the situation and greatly increase your earnings. It just doesn't make sense to me.
As I do agree that Google owns a lot, if they owned the world, then they'd own the adult industry also.
Adult and gambling are easily the biggest paying areas online. A black-label Google would make a killing. They like the squeeky clean image though.
Who knows google run a undercover company that is treating adult ad natures. At least be happy that this giant leave that portion to others.
They also have safe-search as well. They have to index adult/gambling pages in search as they want to be the most comprehensive search engine on the market.
Google would never do this straight up. I know they already do cater to a few premium places but they try to keep that as secretive as possible. It would be too tough to regulate on websites to make sure people weren't placing adult links on websites that did not have proper licenses and dislaimers etc.