Either an assertion is a conventional belief, which is a truth that has no evidence, or a logical conclusion belief, which they don't fully understand (eg lack of understanding about cause and effect in a study). These concepts are often confused, but neither of them are fundamental to a rational discussion.

A lack of acknowledgement when these biases are discovered, is a compelling reason to eject from a discussion. Discussion is one tool to convert beliefs to truths. Sometimes the beliefs changed are ill-recieved, but it your own or another's.