Why are you assuming he did it because of his legal problems?
You'll note that he was indicted in June 2011, more than a year and a half ago. Throughout this time he must have been under tremendous stress: not knowing whether he'd be spending the next few decades behind bars, and not even knowing when he would find this information out. Months drag on into years and nothing seems to get any better. Your life is on hold until someone else decides what your life will be looking like.
This sort of stress tends to eat away at your insides. You can't make long-term plans of any kind; meet a nice person at the bar and you're reminded that you can't start anything serious since you might be going away for a long time. A thousand tiny reminders every day that you are already a prisoner and will be for an indefinite period while the lawyers are lawyering. All the defendant has is time to think about what prison would be like, how the course of their life is not in their hands. It is a feeling of abject powerlessness.
It's not unfathomable that a person in this situation might look at suicide as the only way to regain control of their life, even if it means ending it prematurely.
Suicide for a defendant can, therefore, seem almost enticing. A siren who sings of a quick and easy escape from seemingly insurmountable troubles. I do not know why he did it, but I have been where he might have gone to in his mind. It is a dark place, and much evil can be wrought there.
RIP Aaron
You're blaming Aaron for taking the supposedly cowardly approach and hurting his friends and family in the process, but what about the people who put him in this position? Are they beyond reproach? What about the people who affected those people? Clearly something fucked up along the way because I don't think Aaron deserved to be in a position where he had to do this because he downloaded bytes from a website.
Someone described the process in which a depressed person takes his/her life with a person standing in the window of a burning building choosing between burning to death and jumping to death. It can basically be the very same thing.
And to a certain degree, jumping just makes your problems disappear - just like that. But saying that the person jumping is selfish because he/she didn't contemplate the consequences? Do you honestly believe that killing yourself is something that people take lightly? That it didn't occur to them that they would be missed? Think. That point of view makes me sick and expressing it makes you extremely selfish in my eyes.
Edit : Also as Udo points out lets stop this line of argument for a bit. Some members of the community either knew Aaron or were affected by his work, lets not subject them to this argument right now.
I don't think anyone disputes that Aaron was probably not in the best of mental health to be facing this kind of thing in the first place, but even for a paragon of stability, a multi-year witchhunt and prosecution by the feds will push you to the limit. I know of a few people who have been in the eye AUSA doom (and some ongoing, like Harborside Health Center), and especially for an individual defendant vs. a group, it's very hard.
I imagine if I were suddenly facing a potential 35 years in prison, I'd be at a pretty high risk of becoming depressed.
Minor nitpick: The "justice" system treats rapists far better. Typical sentencing for rapists is 112 months, of which the typical rapist will serve half, from a system( rape is usually a state-level crime )with conviction rates hovering around 65%. Aaron was facing 3-4 times that, in a system( the federal courts )with a conviction rate over 90%.