Personally, I don't see the point of even giving this 'movement' the time of day. It is nothing but a justification for sexual gratification by deviant minds. Having a lobby about it on Capitol Hill does not validate it, nor make it morally sound.
All nations have taboos. Child sex is viewed differently by cultures world-wide, but some things just come down to common sense, and moral strength. In Africa, many females run entire households at the age of 12. They have kids of their own, and are the matriarchs of their sphere of influence, because the parents are dead, or gone, or out looking for locusts to feed all 15 of their spawn. In that case, culturally, sex is viewed as a means of survival of a bloodline, or family unit. Doesn't make it pretty, or any less evil in many eyes, but it has a function. In America, no. If your gut tells you something is wrong, generally society has gone along with that.
The next thing you know, cannibalism will become a lobby, and so it goes.
These people who push these agenda's are not pushing social changes that can, or will, improve human life. They are thinking about themselves, not the human population.
Thus, it has no real motive but to get them off, and in my book, that's just plain wrong.