Rudeness and anti-social behaviour has always been in the game. Albiet more so since the launch of f2p, I simply chalked it up to more a** holes having access to the game. Yesterday I was playing the Imp side a low level and everybody I grouped with did not talk even when spoken to, just dropped for no apparent reason (sometimes right in the middle of a fight), or would not stay with the group (just running off). It was very annoying so I feel yur pain.
Yeah, that's happened to me. I just started up a new character. I chalk up the running off to not knowing how to play the game and not communicating to not understanding the /group or /general /say commands.
Also consider language barriers, etc.
Also, I sometimes make judgments on whether I should help a new player by their name. Anyone else do that?