Well, a simple explanation comes to my mind.
Every group you mention that was once treated poorly stood up, worked, and fought for their current status.
Women fought for their right to vote, they had to fight their own sons, husbands, and fathers, and lord help us, they even had to fight other women.
African Americans fought a much longer and bloodier battle, standing up and demanding their rights, and demanding that the United States live up to the ideals of it's constitution.
The Jews? It took a nation that tried to exterminate them to wake us up and slap the stupid out of us. It took the horror of the concentration camps and the horror of the very concepts involved before people decided they didn't want to be associated with that kind of thinking.
Homosexuality - Very much like the women, they fought for their rights and recognition, the Homosexuals stood up for themselves.
Now we reach the topic of the Transgendered. Yes I know that there are some out there working diligently for us, but they are few - very few. Most of us are hiding, not willing to participate in our own future for fear of being exposed. This is what BattyBattyBats keeps trying to subtly remind us all of. If you want the world to change about the way they treat and perceive us, we need to stop counting on others to carry our flag and fight our battles.
WE need to stand up
WE need to let people know that there are far more of us than they thought.
We are their neighbors, husbands, friends, and co-workers.
We know that we are a HUGE segment of the population. If we all decided "Damn it, that's enough of this!" and stood together, the world would change instantly.