
You do realize that you're compairing amendments that GIVE rights to US Citizens, to something that would TAKE THEM AWAY from US Citizens.
There is no right to whatever one feels an physical urge to do. On the contrary physical urges are the most heavily regulated of all human endeavors in all times and places. Re-framing the debate as a right to feel an urge and act upon it is not a right only a bastardization of language.
The rights the COTUS enshrines are the rights of a free people to representative government and equal participation in the political process but you are very right in that it is primarily a state issue as it is not a federal issue. Yet the comity clause is another issue. The stickier wicket comes from when State A recognizes a marriage that State B does not but the spouses, orginally married in State A move into State B. However, I'm sure precedent exists for dealing with matters of ages of majority which can also vary from state to state.
BTW - this thread is to be punted to GD as it is a matter of expository supposition not a presentation of evidence.