"Perhaps I am too German to understand this problem, since in Germany, nearly every child is taught by their parents that you should only go into debt if you have really, really good reasons (i.e. almost never, except perhaps for buying a house/flat; and in this case it is a mortgage and not a credit)."

In Germany you typically don't have to pay tens of thousands of dollars for your education like in the US. If you don't have well-off parents you pretty much have to go into debt.