I think quite some people heard of the concept of different kinds of infinity, but don’t know much about how these are defined. That’s why this meme should be inverted, as thinking the infinities described here are the same size is the intuitive answer when you either know nothing or quite something about the definition whereas knowing just a little bit can easily lead you to the wrong answer.

As the described in the wikipedia article in the top level comment, the thing that matters is whether you can construct a mapping (or more precisely, a bijection) from one set to the other. If so, the sets/infinities are of the same “size”.

I think the text tries to make the point that it doesn’t work not because but despite him being black. The argument Perry and others make in this case is not one in the form of material benefits but rather moral ones. A member of a marginalized group makes it big, which is supposed to inspire others from this group. The point is that this form of trickle down economics works just as badly as the “regular” one, which is hardly at all.