I think there are a lot of hidden biases in hiring that no one will overtly acknowledge e.g. personality, gender, attribute of race (yeah I know, but still there are people unaware of their racial biases), ability to take orders, if they are too good and might threaten their job or make them work harder because they will output more completed work, etc.

usually this line of thinking is summed up as the follow question: Can I see myself working with this person for 40+ hours a week?

then they bring down the axe with the following: not a good 'culture' fit and move on to the next candidate and the broken cycle continues.

This is all in addition to the broken whiteboarding challenges.