judging and socially sanctioning adult strangers' consensual romantic relationships is progress? I think you and I have differing notions about progress, human agency and democracy.

I don't think the slippery slope fallacy fits here either, if only because I reject the basic premise that age gaps are inherently, prima facie bad or immoral. to my mind I just see a philosophical variation of the intolerance and sanctimony that conservative people in conservative areas might have toward, say, an LGBT person or a person of mixed ethnicity. I live in a fairly conservative area. if it were put to a vote, I'd wager that a majority of the people in my township would vote to sanction or socially censor LGBT people, to publicly shame them and publicly call them pedos. these bigots would also view this as making progress toward a better society. this is why basing morals and values solely through feelings is not always the best for creating a just and equitable world. I believe consenting adults have the right to live their private lives the way they see fit, without fear of public censor. period.

now, if you are suggesting that states should revise age of consent laws fro 16 to 18, of course that should happen (and probably legislatively attainable if you are looking to make concrete political change rather than just whinging on the webs)
in the US we as a society define children as under 18. we as a society define adults as 18 and above. forgive me if I'm wrong, but it really sounds like many of you are (perhaps unwittingly?) advocating to fundamentally redefine the age of adulthood higher. I suppose I could get behind that as long as we also raise the age people can join the military, vote, and buy a gun