Thats what I can't stand man, its such a hypocrisy. Downloading ROMs whether you own them or not, is still supporting a pirate; because the person who ripped it and then is distributing it, is distributing it illegally.
So if there is a full on ban of ISOs, then follow suit with emulation and roms entirely. Don't make the distinction for one and deny it for another. And as I pointed out, there ARE uses to having the ISO from a UMD one owns; the battery life on a PSP is horrible when the UMD drive needs to work; such is alleviated when one uses an ISO of the same game.