When I started working for UPS, my facility was nearly 100% white but has increasingly become more diverse. Racial/ethic jokes are common among everybody... mostly in good fun (but NEVER appropriate) but sometimes not. We can't be certain if the incident took place as described, or if the employee/sup were trading jabs and the employee ultimately got offended and walked out, or if the employee walked out for some other reason....
- Why did the employee not discuss it with somebody else to begin with?
- Why did the employee return to work the next day?
Obviously management took it serious enough to involve HR, which probably investigated somewhat... HR getting involved for non-seniority employees is rare.