The worst behaviour I've ever witnessed on this forum is by newcomers or accidental posters who have totally misunderstood something, are frustrated and get angry because they're not capable of accepting that they're misunderstanding something.
The rest of the bluntness usually comes from experienced forumites who quite simply lose their patience with some youngsters who come here to be spoonfed because they don't want to spend time reading the manual. That's human.
Otherwise, and anyway, the forum manners here are definately as good as on any similar forum. A forum like this with many regular posters who "know" each other since eternity inevitably has some introvert "buddy-club"-features.
Welcome to the real world, Carissa. People are different. Some are capable of expressing their moods in a sophisticated manner, some, especially the ones who don't speak english very well, use more blunt/clumsy expressions. I'm not looking for excuses for bad manners, but this is a forum of average people from all over.
A music maker can be a recovering mental patient, truck driver or a professor of chinese litterature. On a forum of chinese litterature you'll find a more homogenous user base with more homogenous behaviour.
Usually, when someone goes badly out line here, it's the regular writers who put the barker in the cage. I believe you have just stumbled over a spot of bad posts :o)
(X1 invited a lot of newcomers here, and the bugs in it did arouse hotter discussion than normal)