They were out of order acting like that to Buffy. Like who does Anya think she is, Telling Buffy she thinks shes better than everyone. I never thought Buffy thought that. Willow and Dawn were way wrong too. At least Spike ends up putting them in their place.
Buffy admits that she thinks that. In "Conversations with Dead People," to the vamp she chats with. It seems that both sides had valid points. I can see her friends, especially Xander, freaking out, given that she HAS made bad decisions, and it's not like they hadn't questioned interfered with her choices before when they thought they could make better ones. She had no official authority, no one seems to indicate that the Slayer has supernatural planning skills, and I think it is philosophically dangerous using a crisis to justify dictatorship. At the same time, those who disagreed with Buffy should have LEFT rather than throwing her out.