> The impoverished of any race are more susceptible to police violence, and impoverished Black people even more so
is true. But the statement
> Black people of all economic classes are more susceptible to police violence
is also true. There is no logical contradiction between the two. Therefore, when someone responds to the second statement with the first, their response carries the connotation that the first statement is somehow "more true". It implicitly minimizes the struggle of Black people.
Not everyone who makes the first statement in response to the second intends minimize the struggle of Black people, but I think in the majority of cases that is exactly what they intend to do.
There is no contradiction between the two, but only one of them is considered socially acceptable in certain circles, these days, in any context. That's problematic.