...did you just say that it is legal to use backup loaders in a criminal way in the US?
Other than that, you're only partially correct. For one, backup loaders are only legal if they contain 100% own code. Some emulators, like the PSX one, rely on parts of the BIOS, which is owned by the manufacturer of the thing (sony). As such, a legal way to use it is...well, actually pretty hard.
And you're also completely missing the main problem: you are only allowed to use those loaders for
backups. In other words: only for the games you legally own (I'm not sure if that includes region, but it might be).
That is what piracy is, not the distribution of it. Though that is (obviously) illegal as well. Even if you own a legitimate version of the game.