the raid leader in question probably wanted either a fast run, or good geared people. lets say the raid leader in question isnt that knowledgeable when it comes to the game in general. and he has heared that major PvP gear is worse than full PvE. he want it to go as smoothly a possible and hopes that nothing fucks it up. lets say hes pretty nervous aswell because he havent been leading many raids before. now organizing raids, even pugs are tedius and requiers attention. to get the right comps, makign sure the tanks are actually tanks etc. ok all is set. "i need dps!"
whispers are flowing in with people that wants to join and the person leading it needs to keep an eye on both raid chat and all the whispers.
this guy with full 359 promise 20k (blargurlz) dps. inspect, invite. this continues untill 1 spot is left.
now 2 people have whispered him. someone in full PvE, mediocre dps for his gear and achivements for most bosses.
and the other guy is this hunter in PvP items with achivements and all. (reffering to OP)
So the pug leader invites the first guy because full PvE sounds better than some PvP some PvE. beeing pressured by a group that miss 1 guy. probably a few idiots yelling at him to hurry up or they will leave, I too wouldnt bother to much with the choice.
so he has the full group (more or less). and is still getting whisperes form the 2nd guy about checking dummies, about an high progressed main etc. he simply cant give you the time becasue tehy are about to clear the first trash. so he gives you a snide remark to bugger off as he tries to keep his pug from failing.
I guess the point of this post is to make you realize that there might have been more to it than you think.
now take this post, remove all typos and eventuall gramatical errors before your eyes start to bleed (this is what i get for posting at 7am...)