- african americans are statistically more likely to originate from lower on socio economic ladder than, say, asian americans
Thus when you get a bunch of job applicants, you might get an asian american with a Yale degree (James) and an african american with a community college degree (John). Affirmative action or other DEI pressures might force you to hire both James and John, but James will probably be able to outperform John due to higher initial degree of education. Furthermore, James may have had parents who networked and ensured he got good internships and experience growing up while John didn't have that opportunity.
So it's not that the company is offering John a "dog job", it's just, James's capacity to perform in current role and take on new responsibilities is at a higher initial state than John's, so it's not unthinkable he would climb corporate ladder faster than John given those initial advantages. Pay gap is a natural consequence that follows.