most rules are created in the fairy tail assumption that people online have both common sense and respect for other players.

On the internet, this is generally not the case, so they are vague in the sense that a GM can determine if a behaviour is disruptive or harassing and act accordingly, and have their decision covered. If they were laid out in a rock solid manner, there are those people who would push it to the limit and then proudly say "well, I didnt do exactly this.. so its fine... you cant touch me".

I dont mind strict enforcement, but its impossible to come up with a codified laid out list of rules for player that wouldnt involve hundreds of pages to wade through since we all know at least someone that would push it to the brink just to take advantage of a loophole.