Well I agree with Guest a little bit, it's a bit condescending to sit in judgement from a distance. What a lot of posters tend to ignore or not even know exists, is the difference in national senses of humour. I've seen people get upset at remarks on here that are everyday currency in some circles. As has been said on other threads, stop, stand back, and think whether the post actually means what you think it does, before you jump in with both feet and make an arse of yourself, or start an argument.
The NI threads are a prime example of this 'different cultural outlook' there are those who lived amongst it in NI, there are those who lived with it, on the UK mainland, there are those to whom it is a romantic historic familial, but distant ideal, and never the three shall see eye to eye.
Instead of proscribing how people should post, try looking at things from their point of view, that might help.
Giok