Someone having "SEX!!etc" in his signature or a mention of something is a bit different from actual talk about sex. Talking about "sex issues" is not the same as mentioning the word "sex" or something like that. That seems to be obvious. I might have phrased it wrongly, the rule is a bit more nuanced probably, but mostly it's right. And no, it wasn't added after that conversation (what conversation?)

Tublear, that all contracts say something does not make it useless. It's still true and you are still bound to them. We have the right to edit, close and delete threads despite that that text is in more than one forum.

The basic rules are in the registration agreement, btw: