Pretty weird that the story doesn't involve him bringing up the problem with HR or other engineering managers. The people who do the main revenue-generating work of a company (e.g. engineers in a tech company, the finance people in an investment bank) usually have a lot more power in an organization than HR / recruiting. So if he didn't do that, does that make him complicit in the racism? Or if he did try and got stonewalled, he should share that, along with the name of the company.

And it doesn't smell right that an organization would risk giving a bunch of candidates food poisoning and getting a lawsuit by serving them day-old catered food. I'm certainly willing to believe it could happen, but 'extraordinary claims require extraordinary evidence' - in this case I'd settle for him giving the name of the company so that either others can confirm, or they can rebut.