The line is,
don't fuck with google Adsense.Because, like it or not, that's how we're funding ourselves as a site. And if you note
here the whole thing gets even more ridiculous as it prohibits things related to family planning and fetal healthcare.
It's that strict and it's a necessary evil.
The lines exist to keep users from blowing the funding (again) as opposed to some sort of arbitrary prudishness on our part.
What
@Rilla said is absolutely right, but the standard we are using is the Google one-- it's not some sort of personal morality thing on our part. We don't like it, we want to figure out ways to allow an opt-in for adult content that keeps Google out of it (and thus, doesn't endanger adsense/site funding), but in the meantime, it's a necessary evil.