The people who spread the "living document" myth are those people who would like the Constitution to say something other than what it does say (or in addition to what it does say), but know that they lack the popular and political support to have an amendment passed by Congress and the required number of states.
Such people have, for the past 100 years or so, silently and steadily have campaigned to get similarly-deluded jurists onto appellate courts, so that they could "interpret" the Constitution and laws to mean what they want it to mean. Just this week, Justice Ginsberg revealed herself for the political hack that she has always been, then after taking heat from her Lefty cronies, tried to roll it back. This was akin to a retired professional wrestler admitting that it's all scripted. Not really a surprise.
Any time you see an appellate court decision that runs more than 50 pages, the writer is NOT trying to explain how the law and constitution can be applied to the facts of the case; they are trying to explain why the Constitution MEANS something entirely different from what it SAYS. And this takes a lot of pages to accomplish.
Consider: the Fourth Amendment says, in essence, that the Government may not conduct random searches of people's stuff - they must either have a search warrant or the search must be pursuant to a lawful arrest.
And from this, we get the principle that the state of Connecticut cannot outlaw artificial birth control pills. And that states' sodomy laws are "unconstitutional."
Whether you agree or not with the propositions (and of course Lefty's tend to agree), the point is that there is NOTHING in the Constitution or in any amendment to the Constitution that gives the U.S. Supreme court the right to strike down these state laws. Those "Constitutional" principles are all made-up nonsense, promulgated by judges who believe in a "living Constitution."
Leftists are evil, anti-democratic, bastards.