The people saying what a twat someone is, are for the mods to deal with, as repetitive and insulting continual comments harrassing a user, wether the user actually cares much or not, are for them to sort out in order to clean up the forum, the rules on such things are clear, and anyone mistaking this site for bebo just needs reminding its not.
As no one with a life wants to read that rubbish all day obviously, and if they do, they can go to bebo or whatever anyway they dont need to be on a car forum to read childish rubbish continually. Small amounts of banter can be entertaining, but page after page of the same repetitive insults are utterly pointless.
So that side of things is easily sorted with better moderation, quick infraction to half a dozen users to point out to them that a thread about engines isnt the time or place to be commenting on who they do or dont like, and problem solved with regards to comments about others, then you just ignore the ones you dont want to read posts from, and everyone is happy as the thread is entirely on topic for everyone and no one has to read any comments from people they would rather not.