The Scoobies are absolutely right, Buffy is absolutely wrong (this is where she starts to diminish, in my eyes) and I'm a bit shocked that you, Buffy/Angel non-'shipper that you are, take the "she had to kill Angel, boohoohoo!" 'shipper position here. She also lies to them throughout the episode (she doesn't tell them about the ensouling issue until the end of FH&T), starting a very bad trend.
But this is the sort of discussion that takes pages and pages and pages of point-by-point dissection, and I doubt there's space for it here. At least you hate the stupid "Hootenanny" speech, too.
(And the only reason Giles doesn't blow up at Buffy is because he isn't at the party then. He's passive-aggressively avoiding the issues just as much as everyone else is.)
One of the last Great Buffy Quips: "Hey, Pat!" (spade to the eyes) "Made you look." As Xander said last episode, you never miss them until they're gone…