I think he had some assets from Reddit, as well as some of the work being pro bono, and contributions.
Killing yourself over $1.5mm in debt is not rational. You can default on it and go bankrupt and be back to normal in 7-10 years. You can get most of it written off. You can do consulting for 5-10 years and live slightly frugally and probably pay enough of it off to have the rest written off. You can start 1/1000th of a kind-of-shitty photo sharing site. You can flee to China, start over, and no one will pursue you.
They basically don't expect you to put 100% of your income toward fines, back taxes, etc. even if it's to the Government (and hence can't be discharged in bankruptcy). In that case, you just live on 25-50k post-tax and either hide a bunch of cash income while making small payments, or find benefactors who cover most of your costs and work on free software or something.
We essentially ended debtors prisons a long time ago.
35 years in federal prison might actually be a case for killing yourself (although I'd just read a lot of books and be the hacker Mumia Abu-Jamal, and hopefully get out on appeal).