Many users prefer not to have adult content included in their search results ( especially if kids use the same computer). Google's SafeSearch filters provide you.
I did read about the rich snippets not allowing adult content but official response as we the webmaster that work with adult content are the first.
21 Practical Tips for Beginning Adult Webmasters declarations to keep minors out, but you must try to do something to keep children away from adult content.
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SafeSearch page filtering removal request in Google Webmaster Tools Google doesn't show advertisements when sexual words are in the content.