Because google can't control the ads there. Incoming advertisers they can control but outgoing ads they can't. They can only hope that their formula works to match the correct text to the correct ads.
There is nothing wrong with Porno dvd movies. Todays society is extremely hypocritical. The General population (about 90%) are sheep that follow the society so called morals and beliefs. To me, it's F'ed up! I believe Google adwords have alot of owners that own porn websites. I own a site call triple x tasty and its pretty clean looking site and you dont see women naked and see their pussy spread out all over my web pages. You only see pages with movie titles and pictures. My site is attractive looking. F Google!
I think porn is the largest niche on the internet. Guessing it doesn't pay very well either. Unless your counting sites where you can network. Just saying for general websites.
Not every society in the world are same. In my country porn sites were blocked. So Google has to think global way.
They need to maintain their reputation. Just like every other hypocrite, Google denies the fact that the world needs pornography
I actually dont like the adult site that much. but i think it is also a part of our daily life, nobody can avoid it.
Porn sites are only cheap enjoyment, nothing else. Good people do not promote it. IT's waste of time and some times money also. Would you like your child to catch you browsing porn sites or your mom/dead or your boss???
They don't allow casino, alcohol or porn because in many societies there are laws against this, so google don't want to waste money on lawsuits, so they say no to several things, but not because they think it's bad, only because of the laws in different countries beginning by USA's laws