Whilst we, as a guild, crack down hard on anyone unfairly attacking players who aren't so good, we've tended to be more lenient about individuals unfairly attacking players who play very well, and achieve a lot. This is not on.
PCG is a Guild for ALL players, regardless of skill or commitment levels. We work hard to offer something for everyone, and attacking someone for being a strong player or a hardcore raider is JUST AS BAD as insulting them for being less experienced or skilled.
Many of us, myself included, can sometimes be less than nice to other human beings, and even if it's meant in jest, it may not be taken that way.
As an aside, PCG's Vent is there for everyone, this includes all the channels. Personally, I tend to use Vent when I'm doing something in a group, instead of hopping in by default, simply because I like to listen to music or watch stuff whilst grinding and questing. If you think something's going on that isn't appropriate, ask an Officer to pop in and listen. Also, if you see a group of players in a channel, don't feel like you can't come in and say 'hi'. Unless they're actually in a raid or Arena (always /w one of them to check first), they certainly shouldn't mind.
I understand that you wouldn't want to list names on a public forum, but as Cata says, please /w or send a mail to an Officer with a few more details. If we don't know what's going wrong, we can't do owt to fix it.