Why attend predatory colleges in the US?
A few possibilities:


These people genuinely don't know any better. They think a degree is a degree. I would guess that they come from parents that did not attend college. A friend of mine started at a for-profit school because she really didn't know that there was a difference between my 4 year bachelor degree and her 12 month online degree.
People want to take shortcuts and these schools know that.
These schools spend a lot of money on commercials and marketing to try to convince people to attend. It isn't surprising that people would fall victim if you see a commercial for a school 3 times a day.
These schools also promote their currents/past students to help recruit their friends. I have certainly seen this on my own social media feeds.
I once had a manager at a large company that was working on a degree from a diploma mill because the company was imposing a new policy that all managers had to have a degree, but it didn't matter from where.


So to directly answer your questions: No, a lot of people probably don't look into the details of past student success. The type of people that would do this, aren't the ones being targeted by these schools. And even if they do, you're bound to find some successes (confirmation bias) which the school will proudly advertise.

Unfortunately, these types of schools prey on uneducated people, so while it seems like common sense to us, those people may really be getting tricked and yet the government continues to have surprisingly loose regulation.