"So Congress would have you believe, anyway. They had the power to mandate that the feeding tube be put back in, in such a way that no judge could defy it, and yet they didn't do that. Why?"
The Florida legislature did exactly that, and it was ruled unconstitutional.
This is not what congresss would have me believe, this is what the activist judges decided.
Congress could have mandated an injunction requiring the feeding tube be put back in pending this federal review. They do it all the time - it's called statutory relief, and courts routinely abide by it. Whether the Florida bill ran afoul of the Florida state constitution or not is irrelevant - Congress could have made it stick.