Yeah, I agree with you. There is a right way to do that, and I assumed the comment I was replying to was describing the wrong way to do it given their reaction.

I've ended plenty of interviews early when it's clear the candidate isn't going to work out. I agree there's no point in wasting everyone's time, and hiring is time consuming enough. But there's a way to do it with kindness, and I think everyone in the interviewer's chair should have some sense of how. (That said, there are some candidates that are going to take rejection poorly no matter what - you can control how you treat a candidate but now how they react).