I think that the case you're describing is the exact reason this requirement is important. Lacking credits in an undergraduate degree is a red flag -- why are you missing them? Why didn't you go back and make them up? If you're serious about a formal education, the lack of a few credits shouldn't hold you back.
In my case, I took a full-time job overseas between my JR and SR year making 100k+ in the field I wanted to study. It was an easy answer for my admissions officer who then recommended I be admitted to a MS program.
There's a lot of reasons why you wouldn't finish a degree that are valid. Have you considered asking rather than assuming? What if someone had serious depression or social anxiety? You're making a lot of assumptions on being "serious" and it's honestly pretty naive and silly, borderline offensive, and very common in academia.
> why are you missing them? Why didn't you go back and make them up?
Pretty sure that's asking, and if you find that _borderline offensive_ then you probably need a little bit thicker skin. If you're applying for a top-tier institution, they are going to look for red flags in your transcript, and not finishing your education, no matter the reason, is a red flag that needs to at least be explored. They aren't going to simply _assume_ you had some legitimate excuse for not finishing because many people don't.
I don't think it's fair for you to call it naive and silly for someone to understand your background. No one is saying that your serious depression or social anxiety isn't a legitimate reason, but it's also something that has to be considered. Academic institutions have a graduation rate to protect, and they aren't keen on letting someone in that is a risk to drop out after a couple of semesters -- no matter the reason.
If depression or social anxiety are holding you back in your life that much, it's time to seek help, by the way. As someone who has experienced the same, that is a really good indication that it has gone past a simple mood thing into a serious medical condition.
