So long as they are applying the background check to all potential employees, I don't have an issue with them doing so. My firm performs such checks on all candidates for employment, indeed, we check for more than criminal records.
If the management at the SC plant are selectively, based on race, checking up on folks, that is unfair and that inequity should be addressed. After all, the fact is that black people do not commit the majority of crimes that are unsuccessfully attempted and black people aren't the majority of people who are incarcerated. (http://www.bop.gov/news/quick.jsp
) It is true that a greater percentage of the black population, as compared with other races, is in jail, but the arithmetic of the matter can by itself be the cause for that statistic.