Using the statistics Patrick posted, I would think the low numbers of the low countries would have more to do with the low proportion of blacks/Hispanics compared to the US.
ssshhh. you don't want to be called a racist for pointing out the truth do you.
This has nothing to do with the race of the poor, but rather with the racism of the majority. In places like the Netherlands and Belgium, the poor looked like everyone else, so they instituted a generous welfare state. In america, though many poor are white, a lot of them are a different colour than the ruling race, and therefore it is easy to make racist arguments that they 'deserve' their poverty. The majority do not identify with them due to racism, and are quite happy to see them suffer oppression.