jQuery (and GWT actually as well) was created to overcome the big issue we had not too long ago where something that would work in one browser didn't work in another browser - JavaScript was painful to work with and jQuery came to the rescue.
Fast-forward a little bit and you see that browsers are becoming more and more standards compliant which means jQuery is no longer needed to solve that original pain. For probably the same reason GWT was abandoned.
So those who hate jQuery obviously didn't have to deal with JavaScript in its infant stages, those that did will have somewhat more respect for it and thank it for its great service over the years even if they're no longer using it.