I don't see why it can't do both. It's pretty clear Aerys was a bad guy, but making people mutter a seemingly nonsensical phrase repeatedly is sort of Bran's thing now.

Mark my words, the Mad King saying "burn them all" over and over will prove to be Bran's doing. Either somehow Aerys saw the Walkers through Bran, or.. I don't know what else. Thoughts?