I believe that the point was not that Snoke hasn't been criticized by fans, but rather that there has been far greater hostility directed at Rey, and that therefore the vitriolic hatred from fans can't be because of the stated reasons, which are that there's a character whose great powers haven't been explained.I'm not so sure. The big criticism of Smoke is that he has no backstory. In fact his background is so blank there are no facts to conflict with any skills seen. The Emperor works the same way, all skills are assumed to have been gained legitimately in this mysterious past.