They thought she was stuck in a hell dimension hence why Willow was so adamant on bringing her back, had they known she was in heaven they probably would've left her there.No offense, but I think that that's an oversimplification. Also when Buffy jumped through the portal, they clearly didn't weren't sure what happened to her.
Totally! If your friend is MIA for ages, isn't there a major instinct for concern about what may have happened to them while away? Sure, she's the slayer, but there are things that can hurt her too!Everyone was acting out of pure emotion, which could be understandable, had they had bothered to figure out if Buffy was truly okay. She's the one in true pain here, guys. Can we get back to that for a second?