Fashion. You can break it down to specifics, but IMO it became popular to diss Morosov on FSU after an infamous incident at TEB a few years ago. Few seem to remember that there was a time when Morosov was one of FSU's darlings - back when he was TT's sidekick, fans approved of his emerging role with her skaters, and even commented frequently on his good looks. News that he was to choreograph someone new was often met with great anticipation. When he went out on his own, I think many cheered on his future success. Then, as happens, some fans started to grown tired of his signature choreography or were disappointed when he didn't get results for their favourites, and those who were willing to forgive his indiscretions in the face of true love simply could not forgive him for breaking Shae's heart. As others have mentioned, we're all used to Russian and former USSR skaters and choreographers hopping in and out of each other's beds, but Shae seemed separate from all that. Then he started hooking up with younger skaters he was coaching, which while legal, puts a lot of people off. But the collective dislike only started after that TEB IIRC, and the telling and retelling of that story has resulted in his newly mocking image of being oily, greasy etc. Lesson to those in the skating community: don't mess with FSU.