This might be the clearest and best expressed argument I have heard that points towards including cross-dressers under the "transgender spectrum". It is really interesting when we examine our own journeys through this process. Perhaps we all have been guilty of judging different "types" of gender-variation expressions at some point in our life, no doubt while searching to define ourselves.
For instance, we could say "Well, he is just a degenerate sex-addict that uses women's clothing to get off."
We could also say: "Well, he is a really messed up freak that wants to mutilate his biological body and force others to call him a new name."
Perhaps when we impose a "binary system" onto trans people...i.e. "Well, he is either "just" a CD, OR a "true" transsexual, we are doing a disservice. It's like saying:
"Well, he is "just" a cross-dresser, so it is something we can "talk about" and "compromise" about. Doesn't this invalidate and undermine the variant gender expression?
It almost seems to revolve around the issues of "masculinity" and "femininity". Why are some women "threatened" by men who want to CD? In one of my graduate psychology classes, a women stated:
"Well, I want to be the one that wears the panties."
Not surprisingly, she was very critical of "patriarchy" and "chauvinism" as well, and wanted to put an end to "male dominance" in the culture.