I'm sorry about that, Holden1.
As zelda has explained, the site advertisements are chosen by Google Adsense.
http://en.wikipedia.org/wiki/AdSense
Allegedly, the Adsense program is sensitive to the page content. So, if someone mentions the novels of L Ron Hubbard then scientology ads are inflicted on us. A thread about avatars has a semi-permanent ad on creating your own avatar. I'm afraid that some people have been making humorous alternative election posts in the Lounge. This may conceivably have inadvertently triggered the offending (and offensive) advertisement.
MobileRead's policy is that we won't tolerate hate-speech of any kind. I can't speak for everybody, but I think that I would far rather not have advertisements that lead to a lack of toleration. I apologise for the annoyance caused to you.
I haven't seen the advertisement because I live in Europe. Google Adsense will show ads based on your location. It also thinks that a lot of single men frequent this site, given the occasional adverts for foreign brides.