There are very few circumstances wherein someone could be considered solely a victim, with no culpability for their circumstance at all. To categorize circumstances like student loan default in to these buckets -- sole victim vs sole culpability -- is to create a false dichotomy. Not saying you are, but arguments like these tend to polarize to these two endpoints quickly.
At one point in my career, I worked for a bankruptcy trustee. During that time, I learned some very valuable lessons about creditors and the importance of bankruptcy/default on lending practices. If a lender knows that a debt cannot be defaulted upon and absolved through bankruptcy, their risks are substantially mitigated. They're not eliminated, but again, this about understanding the scales of risk and fault as it relates to credit.
Outside of student loans, most credit is obtained through a process that involves the lending institution weighing the risk that the debtor will be unable to pay. The ultimate risk being that the debtor will file bankruptcy, and the creditor will take a serious haircut on their principal.
With student loans, our policy is guided by the principal that higher education is of monumental importance. Rather than simply make universities part of our public education system -- because government = bad, amirite? -- a set of policies and law making resulted in a system of federally sanctioned/backed lending institutions which were granted special status within the context of the creditor/debtor relationship. Over time, these special affordances have been extended to private lenders who adhere to regulations.
And here we are today. Capital has identified this loophole and is leveraging student debtors' future in ways that is clearly predatory. With no risk of bankruptcy, student loan creditors are empowered to garnish wages at rates up to 25%. What lender wouldn't take that deal? How much would you loan someone if you knew you could take a quarter of their paycheck every week for the rest of their life?
Clearly the debtor holds responsibility to use credit responsibly, but you can't create circumstances like the ones we have today and fall back to "Well, everyone really should just be more responsible." No, we all hold responsibility for the system that we've created, and until it changes, things will only get worse.