Well that is just the culture of this forum.
Different countries, different schools, different class and different family has got different culture. Or sometimes it is just actually the emotions that the poster is trying to portray because whatever he reads disgusts him too much so he got to let it out somehow if not he will die of diarrhoea from taking too much junk.
I don't think you can change it and it is still good. New comers will take notice of this and not get affected by this in the long run.
The Logical Player: It works for you because maybe your friend has never go around talking aobut people. You can talk nicely and people will still take and accept. If your friend has been going around insulting then what he say will obviously weight nothing because then, you will see more of that as his new hobby and not really of kind intentions for you to improve.
So yea, just let this be.