Why Fire Them Due To Ethnicity?

Today was apparently an afternoon for long lines.  Over the last few years, this Trade Fair supermarket has changed management several times.  Each time, a new ethnicity appears.  It used to be a quick-moving experience to shop there and check-out.  
     Then, an Indian manager arrived, he promptly fired the cashiers, and he replaced them with Indian women.  Slow women.  Computer-illiterate, unable to move quickly, and uncaring to the customers.  Then, a Haitian guy became manager.  All the cashiers were suddenly darker skinned... and yet equally inept.  Longer lines ensued.  Next, a Pakistan fellow became manager.  Guess what nationality he replaced the cashiers with?  Nobody seemed to care about the stock boys; they have always remained Mexican.  
     One consistency: they never fully staffed all the check-out counters... not even during evening Rush Hours or weekends.  Out of 10 cashier lanes, only 2 or 3 are ever open anymore!
     Why the need for hiring all your own clan?  If the cashiers are efficient and knowledgable, then leave them alone.  "If it ain't broke, don't fix it"  Seemingly hiring people just because they're your ethnicity is absurd, if they're not qualified.  Maybe those races work cheaper than the first cashiers.  Perhaps each manager thinks his customers won't mind waiting extra... just to save him money.  Wrong!  Cost-cutting and "bias of hiring" is only costing the supermarket its customers.