I couldn't believe he had the nerve to refer to Buffy's grief and guilt over having to send Angel to HELL "guy troubles".
He was merely exaggerating. Or you think that Xander actually regards the Angelus affair as merely guy trouble? And Buffy pretty much provoked that reaction by playing the jealousy card as an explanation why she couldn't have gone to Xander for support. Low blow to answer a low blow. Not nice, but very human, IMO.
Let's also not forget that when Xander was in a similar situation and his friend was vamped and dusted he didn't run away for three months. Xander doesn't know that Angel got his soul back and Buffy had loudly proclaimed how ready she was to finally kill him off in Becoming. If anything, he is giving her mental resilience more credit than he should have. Maybe he is thinking "Buffy didn't break down when she had to kill Ford, didn't stop functioning when Jenny died, so why did she have to run away this time?"
I still say they shouldn't be angry at Buffy because they tried to do her job. It's not like she asked them to.
That's not why they are angry at her. Okay, maybe it's a small contributing factor but the main reason is that the Scoobs think that Buffy has forgotten that friendship is a two way street. They cannot support her emotionally if they don't know where she is or if she is around but plays the "you wouldn't understand" card. She, for her part, doesn't show any curiosity about Willow and Giles recovering from the wounds they had last time she saw them and seems totally absorbed in her own problems (there are like a million Angel flashbacks in Anne, DMP and F, H and T). Now, I am not blaming Buffy for that because her life sucks, to put it quite mildly, but I can totally see why Willow, Xander and Joyce might get the impression that for Buffy they are somewhat disposable, that she feels she can come and go from their lives whenever she wants (the scandals only begin after she tries to run from home once again) and still be entitled to the sympathy and support she was used to receive before running away.
Had it been another show, it would have either gone for instant reconciliation all around or have shown how Buffy is right, right, right and everyone else is wrong, wrong, wrong. What I love about DMP is that everybody has a point and everybody overreacts somewhat. No one is perfect, everybody is human and in character.