That's true, but if all of the magic. demons, and supernatural power has been sucked out of the Buffyverse, (I'm assuming that that would include Willow, but she somehow managed to escape by Fray's time, possibly bringing a few vampires with her to repopulate the world with vampires/lurks, probably as the first part of a plan to bringing back all of the bad stuff) would Angel, as a true being, even exist anymore? Remember, the human who previously occupied that body was a drunken lout named Liam. Angel is primarily the demon who moved into that body when Liam died, tempered by a soul supplied by a bunch of vengeful Gypsies. So, will Angel be the single exception to the "Demons Begone" rule?
(This sounds like another one of those "Astronauts vs Cave Men" subjects.)