That's so not true! Some gay men are crossdressers too!
Listen. Rather than debate endlessly about what "transgender" means, and what "crossdresser" means, why don't you simply fill in the blanks below using the bubble diagram I posted in #8.
I'll bet my bottom dollar that you will say, "I am a heterosexual male who identifies as a crossdresser and I present in a feminine manner.
Now. Someone else might say, "I am a straight male who identifies as bigender and I sometimes present in a feminine manner." Note that this person is a CDer too.
So is, "I am a bi male who identifies as transgender and I sometimes present in a feminine manner."
As is, "I am a gay intersex male who identifies as bigender and I sometimes present in a feminine manner."
And so is, "I am a straight intersex male who identifies as a crossdresser and I sometimes present in a feminine manner."
We can argue until we're blue in the face as to who should call themselves "crossdresser" or "transgender", but it really is meaningless since a whole lot of different people use the same terms to describe themselves.