I know it's not fair but by now we should have been accustomed to Rachel and his past with Phoenix being ignored.
At least the young Jean is using her head and seeking help from those who once have dealt with Phoenix which is already more than the X-mens and the Avengers have done during AvX.
Considering the problems Carol is facing understand that she react in this way but Beast and Kitty better than anyone else they should understand what a vision of Phoenix means.