They perceive us to be judging them (we are) because they perceive us as better than they are (we are). So in their fat-addled brains, that must mean that if they pretend they're better than us, that means we perceive them as better than us and therefore that they are judging us negatively or putting us down. Or that's my guess anyways. I've seen this sort of dynamic in other relationships and that's the most logical (illogical?) conclusion I can come to