I tend to side with the Scoobies and Joyce during this episode. While I agree that attacking Buffy in such a public way was pretty crappy (and they probably were a bit too harsh on her) I understand their grievances and frustration with her, and I think everything had to come out in order for them all to move on.
Dead Man’s Party quite brilliantly showcases what happens when friends are not only separated for long periods of time but have feelings of resentment bubbling beneath the surface. I think the thing to remember when viewing this episode is that while we the audience know what Buffy’s been through and where she’s been and that she’s been fine, the Scoobies don’t. All they know is that Buffy went to kill Angel and then disappeared. She left with no warning, no explanation and no goodbye. They have watched Joyce and Giles stress themselves to the breaking point for months, they have seen Giles flying all over the country trying to find her and, as Willow points out, they also needed her over the summer, not just as the Slayer but as their friend. Who knows how many sleepless nights they spent, wondering where she was, worried about whether or not she was even alive.
As for Joyce, god knows what she endured over that summer. Her child was missing and she had no idea where Buffy was, if she was safe, if she was alive. Her misdirected anger at Giles is perhaps unjustified but very understandable, as Giles did help to hide a significant part of Buffy’s life from Joyce. And yes, Joyce told Buffy that if she left the house to not think about coming back, but honestly, I really don’t think she meant it. She had just been bombarded with a huge revelation and she was trying to get her daughter to talk to her, trying to keep Buffy safe, and Buffy got physical with her and stormed out. Joyce said what she did in the heat of the moment, never believing that Buffy would actually disappear. At the very least Buffy could have contacted her mother to let her know that she was alive and safe. I cannot imagine the pain and terror Joyce went through during those months, the anguish she would have felt at not knowing what happened to her daughter. No parent should have to go through that.
I know Buffy was going through a lot at the end of Season 2. Having to kill Angel right after he was re-ensouled must have been devastating. But in her grief, she acted incredibly selfishly. She just left, without thought to what her disappearance would do to everyone. She gave no thought to her mother, her friends, her Watcher and she let them believe the worst for three months and then returned, expecting everything to fall back into place. Not bloody likely.
Really, everyone kind of sucked in this episode. The Scoobies inviting everyone to Buffy’s house without checking with her sucked, as did their very public ganging-up on her (even if what they had to say to her was completely warranted). Buffy believing that everything could go back to normal and not even considering the hell she’d put them all through sucked. Joyce confronting Buffy in front of everyone sucked. Everyone just kind of sucked.
That being said, at the very least, this episode clears the air. Everyone gets their grievances out and once the big confrontation/showdown happens, they all move on quite happily. So, as uncomfortable and awful as certain events in this episode are, they had to happen in order for the characters to move forward and once everything has been said and done, the characters are able to heal and regain their relationships and friendships with Buffy.