The subtext of this argument is obviously, "prosecutors are self-interested, and what they claim to think has nothing to do with what they really think, which is 'I am going to pursue whichever cases present the best opportunity for career advancement'." This, too, is a dumb way to think, because however much prosecutors may or may not think that way, judges and juries do not think that way, nor do they believe prosecutors are entirely animated by career concerns.
No, a prosecutor's job is not to seek justice, their job in adversarial legal system is to prosecute a case in the guidelines of the law. Its pretty clear that the prosecutor has a case against Aaron and its not their job to decide on whether the law is "just" or "right" their job is to prosecute that case to the fullest extent of the law. The last thing we need are prosecutors choosing what laws should and should not be enforced.
Its the judge and jury's job to decide what and what is not just.
http://scholar.google.com/scholar_case?case=5318644154387676...
Prosecutorial discretion doesn't enter into this case; this is a prosecution-driven case. They are bringing this case very deliberately.
What does putting him in prison accomplish? Obviously they're prosecuting him just because he broke a law. Not because he hurt anyone, or because he stole a bunch of money, or because he is a danger to society. They're trying to put him in prison as punishment for breaking a rule. Which is fine, except that in this case, he's obviously someone capable of making meaningful contributions to society. It just doesn't make sense to lock him up like they're trying to.
And all of this doesn't mean he shouldn't be punished--its just very plain to see that prosecutors have a job to do, and being sympathetic to who they're prosecuting isn't part of their job. If they're particularly good at their job, it would be a net loss to society.