You assume that somebody who bases an opinion on somebody else on his wealth is obsessed with it. You would be right if and only if you were taking about conscious decision-making only. But people don't work like that. We're affected by a lot of biases that we might deny or not even aware of. It doesn't make sense to label somebody who is affected by this bias as a person necessarily obsessed with wealth; most likely, they are a very nice person who honestly thinks that they don't care for how much somebody else makes.