I don't expect this to fix all problems, but this could help.
When people start to go TOO off-topic with threads such as this : http://ponyville.us/pony/res/495892.html
, they should be given a warning. Not a ban. Just a warning. Some off-topic is fine because that's natural but perhaps in general replies should be less negative and less arguing about people on a personal-level if it was not even the purpose of the thread to become personal.
It would appear that this keeps happening and solves next to nothing. Steam of course would have to follow the same rule here.