It's about a mindset of the purpose and necessity of imprisoning so many people, not an individual case.
Aside from that, do you believe that Elon Musk in particular deserves to have his freedom restricted, be in a potentially dangerous situation (even in low security), and be locked away from society because of a series of tweets that heavily jumped the gun and stated funding as "secured" when it wasn't?
Being barred from serving as Chairman for three years and being forced to step down in addition to a $20m fine doesn't seem to satisfy some people's bloodlust, I have my doubts that being forced to step down as Tesla CEO would.
Why wouldn't being banned from serving as CEO or Chairman of any publicly traded company for some certain amount of time be enough? Why wouldn't increasing the fine be enough? Say it were $40m, $80m, $100m.
You can punish someone without throwing them into a box. I don't see how that benefits Musk or society in any way. If he's unlikely to do anything like this again, he had power taken away from him, and investors recooped losses, what possible gain is there?
I don't think most people are concerned with CEOs of large corporations overflowing the prisons.