I think that in certain social circles it's already not that big of a deal -- not that the straight guys in those circles are necessarily champing at the bit to sleep with a transwoman, but if confronted with the prospect they're not going to react with revulsion or violence -- and I think that the attitude is spreading.

I'm not sure that comparing "fucking while trans" to "fucking someone who didn't consent" is going to help that, though. Truth-value of the comparison aside (which I find problematic as a separate topic), I think this is as helpful to transpeople getting accepted as serious discussion of whether gay people are more likely to be child-molesters. You can sit down and curiously pore over the data to answer this vital question all you want, but the fact that this is even a matter for serious discourse is both a sign of a problem in the way we view transpeople, and a really really good way to perpetuate transphobic attitudes like "trans people are liars" and "trans people are rapists."