This would seem to indicate that it's a personal bias, and not some kind of technical requirement.
Maybe, maybe not. It was certainly unprofessional; I won't argue that. But it's also the kind of thing I might say as a joke to a friend afterward without attaching any real meaning to it at all.
Suppose I interview an engineer and it goes badly. We have an up-or-down vote after his series of interviews and decide not to hire him. At that point, I could see telling jokes like "...and I'd never hire someone with Perl on their resume, anyway." We'd all laugh and move on to the next person. In fact, though, if the candidate was good then it would never come up again. It absolutely would *not* prevent us from hiring someone and wouldn't even remotely be a weighted factor.
I suspect it was a similar throwaway comment that didn't actually reflect the judge's true feeling, but was meant as something his coworkers would find amusing (even as they understood it was utterly lighthearted). It was obviously a bad idea to joke about it somewhere as public as Facebook, but doubt that it truly reflected any personal biases.