The rules are ideally there to prevent this from happening, but like some other people have stated they need to be stated more.
I'm not sure closing threads like this is a good idea, I mean, they could always elaborate after their initial first try. Things that put me off when joining a new forum are my threads being closed, it's like, "Okay, my thread has been closed for a trivial reason, why am I even bothering?" but at the same time, they're being closed to encourage a change in the users' future post(s), but it can really go the other way.
There is an option in VBulletin to send an introduction post to new users who join the forum, you can put anything into there. I believe this feature could be put to use, with a friendly welcome message, as well as explaining how things work here,
while remaining friendly and welcoming. The
FAQ section could also be put to more use, with regular questions and scenarios that crop up, such as "I would like to advertise my Playerworld to recruit some staff, what should I do?" "The Playerworld Staff Openings forum is perfect for users who have worlds they need help on, blah blah blah.."
As for the attitudes of some users towards others, especially new people, well I had a problem against this for a long time. It seems people are ignorant to people to fit in, argue to fit in and it seems to have become a sort of vicious cycle. I'm not sure how you could change that, although I do believe that this is the reasoning behind some of the forum rules that have been put into place and I appreciate that.