I think the reason Five Whys seems silly to a lot of engineers (or engineer-minded types) is because we naturally progress through the first few whys on our own

I think the reason Five Whys seems silly to a lot of engineers (or engineer-minded types) is because we naturally progress through the first few whys on our own. Our entire work is basically: "That didn't work—why? Because this function didn't get called—why? Because this if-else branch went the wrong way—why?" Other fields don't immediately critique facts when presented to them. They're asked to update a model before the 12PM call and the get right on it. Five Whys gives them a framework for pausing, thinking, and critiquing their tasks before they set off on them. I'll note that the engineer's default criticism isn't always positive: sometimes engineers overly-question and end up derailing the actual work. Critique is important, but sometimes executing according to the plan is more important.