If you don't have pride in your guild, then why would you stay?
If you feel you are so much better than everyone else, then why don't you go?
Do you want a safe haven, where you can take as much as you want (from the gbank, help leveling alts, etc.) without anyone expecting you to give back?
The people in the guild who do give a damn will not stand idly by as you slam our guild's good name in a global chat channel as a means of inflating your own sense of self.
Shit talking happens. But to shit talk your own guild, in a channel that contains a bunch of them? Priceless. Simply, priceless.
I do hope you have the good sense to apologize to the guildies whom you offended. If not, have a nice day and don't let the door hit you in the ass on the way out.