The whole thing about how some members of the band were doing drugs and it was causing a lot of tension, among other things. I guess the whole drugs thing was common knowledge but it's back in the post about her leaving if you're curious. It just doesn't surprise me that she wouldn't want to get involved with them/be around that again.
If she is straight edge and it caused enough tension to leave the band, that's fine. But if drugs were the only reason for the "hurt", that is so silly. Sounds like there must be something more. I don't think we need to know though. Too many music fans are interested in real time drama.