Randy's point was that Nikko's performance didn't have the kind of vocals typically associated with a male background vocal. Bringing up Trey Lorenz in I'LL BE THERE isn't a good example because although he was technically listed as a background vocalist, when he did those incredibly high notes he was singing/serving as a duet lead with Mariah (it would even be more correct to say he was soloing as Mariah did drop out and let him cut loose a bit).

I can't stand the AI judges. On a good day, you can only count on one of them to make sense some of the time. If there was one performance that was really a bad STEVIE WONDER impersonation, it was definitely Mario's. Constantine sucked harder than Mario, and not surprisingly, neither one got flack from the judges.