Another non trivial aspect is his offer price. No one seems to be pointing out the obvious half trolling nature of an offer that yet again includes the number 420. In that respect part of his motivation for doing this is self amusement.
I think the people most offended by it tend to be the people who have lost that joie de vivre and miss out on the fact that we're all just existing here and now. Sure, do the very serious things that need to be done for a person with his resources, but in the end, we can't even prove it's not all just a damn simulation can we.