i think he's referring to the collar (not the skin) as in white collar work vs blue or brown collar.

The US is a white-majority country where the power and money are disproportionately in the hands of white people.

When a company (in education!) that makes lots of noise about diversity obviously favors hiring white people, it's noteworthy.

If we were in some brown-majority country where white people were excluded from money and power, yes, that would be noteworthy. Call it out! The US, despite what Trump tells his MAGA followers, is not that country.

For a workplace to be very white means they are self-selecting whiteness for their employees instead of hiring in a way that gives equal opportunity to all people. In other words, they have (probably unconscious but still inexcusable) racism in their hiring practices. Reasonable people would agree this is a bad thing.