I think we can compare apples to apples. If a creative writing graduate needs a job, she may join McDonalds or she may join a government in-house cafeteria. In both cases, she’s providing food to customers. Do you think that the government employee is serving the public in a different way than the McDonalds employee?
Equally, we can compare the public defender to a lawyer working for a small law firm serving low-fee customers. Does the public defender deserve to have her school debt paid more than the lawyer working for the small private law firm? I don’t see why.