Because sexual health isn't something we should be embarrassed to talk about and it is something important to quite a lot of students. As a responsible student site, TSR should support students in all aspects of their health and well-being.
However, as there are children on this site, they are not allowed to go into detail about positions etc (if a moderator sees something that is far too detailed they would remove the post/thread or edit it out).
As there are children on the site, this is why everything is sensored. Plus TSR doesn't want to create a hostile environment and some people are just sensitive to swear words/rude things.