In my experience, good players almost never encounter these horrible df attitudes.
It's the bad players who trigger nasty attitudes from people and feel like everyone is nasty in df. Most people who snap at bad players in df aren't neccesarily douches, they could just be stressed out trying to get something done and then have to deal with terrible players.

Before you start saying my attitude is bad after reading this, I helped plenty players who weren't good, but had potential clear things and improve and I never throw a hissy fit in party chat when I'm stuck with terrible players that add 40 minutes to a dungeon run, altho I do get annoyed and vent about it in my static's linkshell.