Can I just say again how f*cking annoying it is that the Buffy world treats Angel as completely responsible for everything he does when he’s Angelus? After Buffy’s big speech to Ford about how when you’re turned, a demon moves in who isn’t you? Hell, Xander killed his friend Jesse in the first episode or something, does that make him a murderer?
(Yes, sometimes reruns are a bad thing when you’re trying to have a lazy Sunday.)
In the series they started out saying “It’s completely different” but as time went on they explored the idea that there was still something of the original person inside the vampire. I think they also sometimes blamed him for the original decision to become a vampire. Giles and Xander didn’t really need any complicated reasons.