I think that's the point. At the same time as the activists....and many non-activist who want to be "on the right side of history" repeat the refrain: "If it feels good do it", when faced with the ugly truth of what that really means, they will reject the logical end of that position.
The debate should not be about internal desires driving morality and legality, but about why some behaviors that may be rooted in innate predisposition (assuming that exists) may still be immoral and should be illegal.
By many, this is also a continuing quest to tear down "old timey" mores and standards. The foundation upon which many of those old timey ideas were supported are considered to be forcing another's morality down other's throats. With that in mind, who gets to choose the new foundation of what is moral and is not? Especially when it excludes others'?