So what? If any legislature votes to lower the age of adulthood, that is the state's business.
If a state ever determines that a 12 year-old can vote, if a state ever determines that a 12 year-old can own property in his own name and sign contracts and have all the other rights and responsibilities of adulthood, then and only then does a 12 year-old have the right to engage in whatever consentual sexual practices they want. That's what being a adult means.
Seems to me that your beef is with anyone who would lower the age of majority. I would agree, since I don't think that most kids are ready for those responsibilities at such an age. But if that's what a state wants, a state should be allowed to do it. It's their business where they want to draw the line between adult and child. It has no real bearing on the conversation except to raise some sort of emotional hackles.
There seems to be a disconnect? The 'state' is not some ethereal arbiter... The 'state' like the federal government is the people -not the judiciary. The people have repeatedly spoken YET the judges overule in favor of what -the lowest common denominator? The judges surely do not respect the people when they consider sodomy to be an unalienable right or when they insert themsel;ves into moral questions reserved to the people...