A decision to start your adult life with borrowing large amount of money and spending it on studying an esoteric subject would be considered extremely irresponsible in most societies ( assuming the person does not have any assets or marketable skills to fall back on).

By 'most societies' you probably mean undeveloped countries.

This problem doesn't really exist in other first world countries.

If you enjoy art history, I have no problem whatsoever if you want to learn about it. But if you borrow $50k that you can't pay back to pay for your hobbies, that's irresponsible.

The problem is a university and/or loan provider who is only interested in your money (and doesn't fear their loans being forgiven) has an incentive to mislead kids into thinking that this is not irresponsible.

Not everyone is as well informed as you were at 18.

The article touches on this, but income based repayment benefits students who graduate with medical, law or other professional degrees the most. Entering into the workforce at a relatively low rate, then having some loans forgiven before their pay goes up a great deal.