Why do you not apply the rarity argument to sodomites too? Under 5% of people are sodomites (the same bar you set for children) so it should also be banned for them to fornicate.

But adult sodomites, as rare as one may argue they happen to be, are legal adults and thus have the full measure of their civil rights. As such, they are a protected or tolerated minority, not an oppressed minority. They are a legitimate component of the gerontocentric hegemony that Ethan seeks to preserve, and circumventing the civil rights of those who have the full measure of their freedom of choice is considerably more difficult than those who lack most of their civil rights - vis a vis, those who are legally considered minors.

Even if a number of anti-choicers want to eventually re-criminalize sodomy or other consensual sexual activities they find offensive or incompatible with the best interests of the status quo, they know they have to start with the easiest targets first, and then gradually work their way down the ladder. They know you have to justify one draconian measure - starting with the easier ones to convince the public to go along with - in order to make it subsequently easier to justify other draconian measures against more difficult targets later.

I'm not saying that Ethan in particular wants to stifle the freedom of choice of anyone who fits into the gerontocentric hegemony, but that is certainly the goal of many conservative elements in society, and anyone purporting to be a progressive who believes we can have a few draconian laws while preserving certain types of democratic freedoms are being quite naive and need to pay attention to some of the major lessons of history a bit better.