But let's suppose you're right. I don't actually think firing would be an disproportioniate rebuke under the circumstances. To use language that Heymann might have used of Swartz, I think it would be great to make an example of him.
All that said, I don't expect it to happen.
He would, without a doubt, make much more money in private practice. That's one thing I think HN folks overlook. Senior DOJ people could lateral out to high six figure into seven figure salaries as partners in law firms. The folks that stay at DOJ as lifers are generally "true believers." That doesn't mean they don't have their internal motivations, but rather those motivations are shaped by an extremely deep belief in the rule of law. They view people who don't follow rules as at best anti-social, and more likely dangerous. Figuring out why they don't understand hackers doesn't require resorting to any elaborate theories about trying to make career-defining prosecutions. They're simply people who have a very different world view than the one hacker culture embraces.