The dichotomy between what’s acceptable and what’s not seems to be one between what is biologically immutable and what you choose to be. I find this argument highly dubious because it rests on the notion that choice by free will is somehow inferior to random biological fate and is therefore open to arbitrary societal regulations. Which is frankly just another way of saying, if I see scope in successfully poking my nose in your business, I bloody well will.
Gay people should de-emphasize the line of argument that they are made that way and they can do nothing about it (it might be so, but still) and stick with the free will angle, because that’s where it truly belongs. Someday the world is going to find a way to mess with your brain and cast you in their mold of preferred sexuality and that day you are going to be very sorry that you had the wrong angle all along.