Except no one has presented any evidence that bad debt is an indicator of job performance issues.

Car insurance providers have a ton of data that correlates all those factors you mentioned, so for the most part it's reasonably fair for them to set rates based on that. No such data exists when it comes to debt and employment, as far as I can see. Just a bunch of people here arguing back and forth for their personal opinion.

There isn't any evidence, it isn't actually true. Debt is inescapable in a country where a trip in an ambulance can wipe out a family's entire income. It's just a cultural prejudice born from the American idolization of free markets (which itself is a vestigial expression of European classism and belief in noble divinity), rugged individualism (and a pathological fear of societal bonds) and the Protestant work ethic, mixed with a bit of racism and xenophobia.