Well, patrickt (welcome to ThePhotoForum, by the way

), we have rules that exclude the form of behaviour you are portraying, so given we mods manage to have our eyes everywhere at all times, day or night (which we don't, hence the alarm buttons!), we see to such posts and might as well remove them and tell the posters that this is all off here.
In general people might leave because a forum is too slow (nothing happening for days), or too crowded (too many new threads appearing over night). Sometimes, TPF is on the brink of having too much going on, but then we soon will have chosen our favourite forums, don't we, and mostly go just there.
What would make me leave a forum would be to be totally ignored, or ridiculed, put down, discriminated against or get flamed. Not that any of this has ever happened to me (thankfully!).
And with regards to this very forum (one of three I go to, the two others both totally NOT photography-related) I don't have a choice ... I just must not leave or else ...

and

by the boss (I think).