I think the OP isn't telling us the full story. No sane GM (especially the one controlling the top guild on the server) would change one of his/her best healers like that. I have seen really good players replaced by weaker ones in the past just because these good players were always whining after a wipe and making the raid night worse than it should be when it is a wipefest.
Another possible reason would be that this new healer is a girl (I hope I'm not right on this) and a close friend/has a personal relationship with the GM so he probably replaced the weakest of the 2-3 healers in raid (you?).
Or maybe he saw more potentional on that healer (regardless of being a male or a female) than you and the only reason you are much better than that healer is because you outgear him/her by a LOT and know raid fights better.
It could be one of these or even the GM replaced you just because he is a noob! Imo you should just spend these 25 bucks to transfer. Else you should quit this game and enjoy life without being stressed by a video game that you are supposed to have fun on. You could also ask officers/core raiders that are close to you why did the GM kicked you. If you have no one to ask for that... then you really can't get along with this guild and you were causing problems for them.
After reading some more posts in page 2 and 3... shame on you for using your sexual orientation as an excuse for being a douche - I'm sure the new healer will be MUCH better than you in the future and that you should either quit or learn to be a better person...
I have left once during DS my group because they wouldn't do HC on g2 and I believed I could tank in g1 more HC bosses than Morchok and Yor'sahj, it didn't make the situation any better and I showed a bad self of mine that I hate even remembering it(yeah, because g2 was holding me back but it was purely because g2 ppl didn't want to progress like g1, they just wanted to have fun and loot from normal which is ok). I apologized to each of the members seperately and never did this again and I have never "raged" on raid chat since then about anyone. If I am mad or think that someone is underperforming I talk with one of my best friends in wow to just get it OFF me and relax.
I will say it again... become a better person, no one likes drama queens and I'm talking from personal experience.