I hear you on this one so allow me to give my 2 cents,
My take:
I'm not going to pretend to understand what someone is feeling regarding their body and gender dysphoria (or identifying as transgender). That said though, I'm able to rationalize the principle of claiming the title of "other"; as it pertains directly to the concept of internal human condition.
Maybe all of this understanding is a product of experience and environment? (I'm connected to a very well known school in Massachusetts which is very proactive for LGBT rights and I live in Cambridge of all places) Probably, although my guess is it runs deeper.
I work part time as a bartender, I hear a lot of views and voices of opinion. I judge, but not as a bigot. Identity is not a character flaw.
I'd say I avoid labeling people with clinical titles (i.e mtf/ftm trans, transgirl, transguy), gender pronouns, and don't view people as such as "weaker" individuals. Most importantly to me, I listen when someone tells me their story.
As for the rest:
For the most part this is a forum containing teens living under someone elses' roof, I'm not at all surprised by the bigotry. Essentially this is a tiny demographic of tumblr's awful opinionated starfishs although without nearly as many richard pics (albeit many pictures of richardheads).
I wouldn't let this tiny microscopic portion of the internet get to you, nothing said here has changed a person's outlook on life and we all know it (THANK GOD). I like you because you've always been very genuine, even when I was just another starfish posting on a block game forum circa 2007.
Best,
J