The difference between the 7 months Swartz was threatened with by prosecutors and "50 years" is the question of whether multiple CFAA counts for the same crime "group". We know the answer to this: they do. Defendants convicted on multiple counts of CFAA offenses for the same underlying criminal act serve a sentence for a single count (the most severe). A judge could override this, but the onus should be on the "50 years" people to cite a CFAA case in which a judge has ever manipulated CFAA grouping rules to amp up a sentence. The argument seems to suggest that a judge might be so upset by Swartz that they'd throw out a chunk of the sentencing guidelines.
Swartz's own attorney wrote, after his death, that a conviction on all counts might still leave Swartz at a sentencing level that allowed probation: his crime was non-remunerative, the statute he was charged on is oriented heavily towards financial crimes, his primary victim was unmotivated, and he had no criminal record.
When Swartz's sentence is brought up on a message board, what's really being discussed is the nature of judicial discretion versus the federal sentencing guidelines.
That's unfortunate. Leaving aside the fact that any custodial sentence for Swartz would have miscarried justice, and beyond the trauma of enduring a federal criminal prosecution, the likely guideline sentence for Swartz's charge (if you stipulate that he was guilty, which you can't do here) is not prima facie insane.
But other CFAA sentences are totally insane. When you handwave around Swartz's sentence, you make it easy for people who understand (at least a bit about) federal sentencing to laugh off other CFAA sentences. But there have been recent cases in which the CFAA's sentencing process is much more clearly unjust.