It's shit like this that has made some bronies lose faith in the fandom. Instead, of discussing Pinkie Pie's character development, most people are arguing about whether the clones were killed or not. (Technically, they were magical energy summoned into being by the original Pinkie Pie. I DON'T BELIEVE, that the spell would've worked on the original Pinkie Pie since she never came from the mirror pool.)
Too be fair, if your stuck with someone who breaks the fourth wall like some insane pariah and get stuck with a million of them, your pretty much sacrifice logic to be spared that. plus you gottta admit those clones have to be stupid to keep trying to be funny after seeing one clone go boom.