The way you described it is spot on, the real question part is what hooks people, then the made up answer just slides in before you notice. I've had luck with exactly one thing when my cousin went down this hole: never argue the conclusion, just keep asking how they'd check it themselves. Ask what test would show them they're wrong, and when the answer is "nothing could," that's usually the moment something clicks, not from me winning but from them hearing their own words. It takes forever and it only works one on one, never in a group where they've got an audience cheering them on. So no, it's not a lost cause, but arguing online in a public thread basically never works, you have to get them alone and be way more patient than you want to be.

A friend of mine skipped base miles and got hurt two weeks in.