Because they said she was being rude and disrespectful to Sage. It was just usual fan trolling and craziness. There was a very popular sage fan on this board and he was probably trolling but he had a lot of users hating on Jean for somehow dissing Sage though the character just says Hi to her. It was over the top as what you can expect here at times.
God, the Sage fans here used to be 10 times worse than the Storm fans now.
And that's saying something.
"We come into this world alone and we leave the same way. The time we spent in between - time spent alive, sharing, learning together... is all that makes life worth living." - Jean Grey