They still can't.
They can (and do) pretend to, though, and the State goes along with the farce. Falsehood is still falsehood.
In a time of universal deceit, telling the truth is a revolutionary act.
-George Orwell
So here's the truth: Adam and Steve can commit themselves to a lifetime of buggery, the State (and even some ostensibly Christian denominations) can play along with the farce ... but Adam and Steve aren't married.
I agree with your post, but could we use another name besides “Steve”? ;^)