There is an enormous difference between a person taking a minute to collect their thoughts without speaking and a person being unwilling or unable to communicate. I can't be sure, but it sounds like at least some people in this thread are talking about pushing back against the former as well as the latter.
I am fine if they think about it for minutes or need a while to sort thoughts out. But at some point I would like to get some response. What else can I go by in the interview? And even if that person can write great code I am not sure things will work in the long run if he can't explain himself.