Good point. Also, even when questions are well-understood by domain experts it still can be very effective to argue about them, since this usually leads to the clearest arguments and explanations. This is especially true since the social norms on this site highly value truth-seeking, epistemic hygiene (including basic intellectual honesty) and scholarship: in many other venues (including some blogs), anti-expertise attitudes do lead to bad outcomes, but this does not seem to apply much on LW.