I've recently been thrown into the position of interviewing many candidates for both more senior roles than I have, and job functions I know nothing about. So I'm totally guilty of this, sorry.

We had a candidate a while ago with lots of experience in many different stacks, but none in the ones we use. I suggested to the hiring manager that ageism might be a factor here, as he clearly could learn new stacks based on his past experience, so it was reasonable to expect he could learn ours and not need as much specific experience up front. We didn't hire him, and I feel that was a bad decision when I look back. We recently started hiring grey haired men again, but only after it was needed by the sales team.