There's a difference between being cognizant of unconscious bias and being disrespectful to your candidate. I am cognizant of unconscious bias, so cognizant that I know it plays a much smaller role in biased outcomes than conscious intended bias. I read candidate resumes and I treat candidates with respect.
The parent is disrespectful to the candidates they interview and I am being charitable in taking their explanation about bias at face value.
It sounds like you've had some combative interviews in the past (it sucks - I've had them too) but that's not the same as being aware of biases.