AdSense site approval: policy violation. What did you do to get it approved?

That certainly would not have helped.
If you run Adsense on content that is clearly controlled by third parties, you’re likely to get banned (or not accepted).

Always make sure to moderate heavily if you want to use Adsense on your forum, or you’ll lose your account the first time someone uploads a picture of a nude woman holding a gun and they notice it before you do.