Yeah, Buffy had about ten seconds of, "How dare you," and then it was over.

And quite aside from messing with people's memories and instincts, what Willow does to Tara (erasing her memories) is exactly what the monks did to all of them. No wonder she thinks it's ok, it's an accepted practice! (And maybe the monks made that the case, too.)

It's a violation when Jonathan does it, but not the monks. Just like the Slayerification spell was a violation when done by African shamans, but not by a white witch. (So much fail there.)