Have you declared bankruptcy before? I have not, but from what I read there are very severe consequences. (Okay okay, our present president being the exception. But if you are not born rich there are bad consequences)
But these things aren't a big deal for most 21 year olds. Certainly they are smaller considerations compared to paying back a high 5 or 6 figure debt.
If student loans became dischargeable through bankruptcy, I imagine that could put pressure on bankruptcy laws in undesirable ways (e.g., the current 7 year period might get extended to 20 years).