It's pretty simple. Sexual orientation wrt gender is the same - if you identify as a male , whether you were born one or not, and you like women, you're straight. If you transition to female and all of a sudden you find you like men, you're still straight. Of course, the LGBTWHATEVERTHEFUCK reject the possibility, because they feel threatened by the possibility - they're afraid that some would attempt to apply the idea that transsexuals can actually legitimately change orientation (as opposed to "no longer being repressed") would be applied to them - even though it happens in the straight world, and in other animals.
It's just not politically correct that someone like me can exist (and others are afraid to speak up for being labeled homophobes or whatever). Me, I don't give a shit about political correctness being used to suppress my legitimacy - and I find it hypocritical that they are using the same tactics that were used against them without feeling the least shame.
Just like they won't admit that the LGBT "community" is fucked up when it comes to having more violence than the rest of the world, or the gay villages being more dangerous for transsexuals than living with the "normals". Or the higher levels of lifestyle diseases from smoking because it's part and parcel of the gay lifestyle. Or the highest level of HIV/AIDS among transwomen and gay crossdressers of any group in the world, because letting some guy hump your ass like a cheap horse in a claims race at Pimlico somehow makes both groups "feel like a woman." Or that the level of violence against transsexuals, that they mourn with their "transsexual day of remembrance", is total bullshit as well - up to 95% of victims are people of color - it's a race problem but they profit from it to have a huge pity party every year. Complete denial of reality and a diversion of resources from solving the real problem. Self-absorbed assholes.
And you should see how much people STILL deny it when confronted with the actual stats, broken down by race, etc. In doing so, they're being racist themselves.