Acknowledging biology is not a form of oppression. Is it oppressive to tell someone about to jump off a roof that they'll fall and get hurt because of gravity? We don't say, "Oh, just let him believe he can fly. It would be cruel and insensitive to tell him about gravity and ruin his fantasy." We know that jumping off a roof will result in bodily harm and suffering so we tell people not to do it. Much in the same way, troons will never be the gender they pretend to be, and their actions will inevitably result in bodily harm and suffering. We should be warning people not to do it for that reason. No matter how much surgery or hormone "therapy" you get, your DNA will still reflect your birth gender. Turning a man into a woman or vice versa is literally impossible with our current technology. Probably even future technology will never be anything more than surgery and hormones that don't change your DNA and don't give you functional female internal organs. Even if in the future they're somehow able to graft a uterus and ovaries into a male torso, that doesn't solve the DNA problem. But, let's pretend science was able to fully transform someone's sex down to the DNA... you're still putting your dick in someone who used to have one, so it's still gay.