I'm curious if you're young enough to have gone through this yourself. The idea that publicly available salary information is enough for a young person who has never supported themselves doesn't really make sense to me. I'm willing to bet that 90% of 18 year olds can't figure out what a reasonable amount to borrow is given salary information. This includes me. The problem isn't an inability to do math, the problem is that there are too many variables that fall under "things you don't know that you don't know." Such as:
What monthly expenses should I expect to pay? (This varies wildly among people I know, there's no easy answer. And knowing rent + utility costs is only part of the puzzle. An 18 year old doesn't appreciate the costs of things that "just come up")
How much money should I plan on NOT spending every month to give myself a buffer against the stress of living paycheck to paycheck?
How much should I expect to be taxed? (Again, the number are out there, but just googling around, I can't find any easy answers that include averages for federal + state + city)
Should I expect to live in an expensive city if I have X career? (Not an easy question to answer for someone who doesn't even know that that career will be)
How much should I really expect to pay for college? (Between yearly tuition increase, variation in scholarships/grants and the differing costs of living on-campus vs off-campus, this is hard to know)
If I have the numbers for the average person in my position, what are the chances that I will be worse off than average?
I guess there's the possibility that I (and many people I know) are exceptionally bad at making personal decisions, despite doing reasonably well in most other aspects of life, but I doubt it.