On the one hand you do need to be able to take some criticism. This includes the random derp who has decided they are gods gift to DPS. On the other hand there is a limit as to what is acceptable in my eyes. Realistically if they truly are that aggrovating eat the timer for ditching the run, and if you feel you have enough to get them spoken to hit up a GM. The community at large is as bad as you let it be. Find yourself a group of folks you like playing with, and enjoy it. If you're dependent on random PUGs ALWAYS, unfortunately those are regularly far too critical of someone not doing something JUST right. YMMV, but your playing for fun, remember that, and adjust as needed so that it stays that way.