Given what you've told me about these people you interacted with, I'd say, if their group goes well, it's more of an indication of the sad state of society rather than a reflection on you. I know a lot of people who want to be all "LGBT-inclusive" but only when it's "fun" or "convenient", and heaven forbid that they actually try to combat their own transphobic thoughts in the process. They have the attitude of "well I say I support it so I can do no wrong."
I say forget 'em, seriously. You're already dealing with enough in your life. You have transition, which believe me, is a bigger stress than it feels and takes a lot out of you, especially early in. You've got your classes to complete, you have your son that you have to take care of, and I am sure many other things that are more worthy of your attention and concern than these "supportive" people.