Maybe black people just don't identify with the system, having been exploited for most of our history here, still not being very high up the ladder and not having as much to lose as some other groups in America.

I mean, we've got our own "illegals" with limited rights that make even less than undocumented migrants and have even less liberty (those in prison). I am not absolving serious criminals of their actions but there is at least an implicit agreement between government and business that a certain group of people is open for exploitation and both are partially complicit in the sheer size of the group as their policies leave little means of escape from that exploited class.

I think black people could be more squarely, politically in support of illegals but, in general, I think there's at least an abstract sense of a shared struggle against exploitation.