Maybe you have trouble understanding that pervasive notion because you misunderstand what people are saying?
Neither I nor the person I replied to said or implied that all Trump supporters are, well, anything. The other fellow talked about "lots of Trump supporters" (which could easily refer to just a few percent of the total) and that's the group I referred to in my reply.
I don't understand the pervasive notion that if you talk bad about any set of Trump supporters, you're somehow painting 63 million people with the same brush.