Why would having a lot of debt make that person have “… some aspirations of foreign travel to risky locales…”?

Plenty of people get into debt just doing normal shit at their homes

High risk behaviors correlate… It’s not a foolproof assumption, but it probably will be true more than half the time.

If we’re going to be that ridiculous about risk management but not other ones that , I at least believe, are in the same tier i.e. alcohol abuse, then we might as well go full bore and have the government pay an extremely generous, generational wealth paying position.

That’s the only way you’re going to get people with self control and willing to live the life of ascetic monks for the duration of time to both learn how to build these systems and then actually build them

Your first paragraph is incoherent… can you try to write out the actual argument legibly?

I think they do try to keep people with substance abuse problems from getting clearance. (Unless they are friends with then President or something like that).

I'm not sure how that's relevant. The goal is to assess the individual's susceptibility to coercion. Maintaining safety from kidnapping while traveling can certainly be a concern when you hold a clearance, but simply taking your family on a vacation overseas is not among the high concerns. If you have bad debt where you are drowning financially, or if you have strong foreign ties or connections, or other behavioral risks, they make you susceptible to coercion. Selling secrets to adversaries to repay loan sharks, being extorted using threats against overseas family members, getting drunk or high and divulging secrets, secrets in exchange for drugs, etc.