Denial is the word that comes to mind. It's a way for some to make themselves feel better about what they do. Sort of the same logic some of the Tri-ess groups use when they say "ALL" crossdressers are straight. It's an attempt to minimize what they see in themselves as a flaw.
By the technical definition I suppose the argument could be made that women crossdress when wearing pants, but it's a semantical and highly outdated concept.