My understanding of this law is that it does not require States to perform same-sex marriages, should the Supreme Court "send it back to the States". It only makes it so that any marriage performed in a State where it is legal must be recognized in every other State as valid.

You may be right about that. I just reread it. Sorry OP, it sounds like Supreme Court could still fuck us.

Which, you know, if we were on the revocation path, the validity of those marriages would then QUICKLY be under scrutiny. Not good by any means.