The vast majority of African Americans are in the lower class.
For a population to reach a higher class, consistent jobs on the lower classes are necessary to provide social and financial capital. Employment teaches hard work, organization, customer service, teamwork, etc. The importance of African Americans having ready and available low income work has been stressed to the likes of you several times now. When Mexicans take African American's job, the economic tradeoff is higher unemployment, crime, imprisonment, etc rates -- or leaving the state entirely. Period. Like
@Tommy Knocks describes, these are real tradeoffs and so when we discuss the issue, it is these realistic tradeoffs we must consider. And the tradeoffs say Mexicans compete directly with blacks, and that their growth must be curbed or stopped. There is no other realistic or feasible option.