Because the average Fox News viewer already knows the real answer, whatever she replies is meaningless to them.
The point is to put the lie out there and let it have a life of its own.
I’d say she should have thrown it back in his face – “the way you and other Republicans talk, it sure sounds like you think voting for a Democrat is a threat to democracy. Is that why you ask this question, you’re really just projecting? Republicans are the ones sowing doubt, spreading conspiracies, threatening voters, sending out fake robocalls, and trying to stop early voting and mail-in voting. Do want people to vote?”
