After life

I am doing my first watch through of Buffy, I am currently on Season 6 episode 3 "After Life". My main question is, why does everyone assume they saved her/pulled her out of hell? I mean, with all the good she's done and all the people she's saved... and they assume she went to hell. Why? Geez no one stands a chance of making it, if they think Buffy was in Hell...