Actually we are. Not enough attention is being given the the three European Court of Human Justice precedents cited in the majority opinion on the Texas case. While the actual way in which these European precedents were used is a little fuzzy, the way I read it is this: The 14th amendment guarantees Americans liberty, and the European Court, combined with whatever US public opinion will more or less stomach, defines what liberty is.
Creating a precedent for our law being determined by foreign courts was simply too high a price to pay for a very few Texas gays not being subject to misapplied prosecutorial discretion.
I agree with you the citation to European precedent is troubling. U.S. courts have often looked to common law precedent in England regarding issues for which there is little U.S. precendent, but looking to continental civil law countries is unheard of - they have a different legal system.
This is of a piece with the SCOTUS habit of finding a "modern trend" against some kind of law out of flimsy evidence and then declaring all laws contrary to the "trend" unconsititutional. It's usurpation of powers not given by the Constitution.
What I am really bothered about is conservatives who didn't like the Texas law think the decision is great, not realizing they are ceding their liberty to the Supreme Court. Hasn't anyone noticed that we can't vote for Supreme Court Justices???