No. You cannot.

Do I donate money to certain projects of mine? Sure. When did I donate the most money? When I billed a private equity firm $300.00 per hour for development work and had a surplus of $15,000.00 dollars. I gave quite a bit to the FSF and others.

Do you really think that by charging the PE firm $50.00 per hour I would be enabling them to donate to the FSF? FreeBSD Foundation? Haskell? GNU? Do you even think they would or care? I certainly wouldn't have enough money to do so at that rate, but I did at $300.00 per hour.

Highly naive my friend. I'm sorry to be offensive but I'm sick of my intelligent peers (sometimes even more intelligent) squandering what is, a massive opportunity sitting in front of them that is being ignored for a totally ridiculous noble cause when their "noble causes" could be enhanced so much more without an iota of evil behavior.

Tarsnap isn't going to become an big evil corporation by charging more. It might if he decides to sell it, but I doubt that. It would be enabling him to do even more amazing things for software, geeks, the world, whatever. Those amazing things could be donations to enable OTHER brilliant people or it could be a new business, or new features that make backups a better experience, or it could be starting an R&D lab for crypto that pumps out purely Open Source research on cryptography that makes its way back into Tarsnap or different business.

Patrick actually answers this point. The shorter is that while people are free to spend as they please to charities, businesses usually don't. He goes on to note that businesses have very different value structures. This means that while I may consider a hundred buck real money, an enterprise business very likely will not. The final bit is that businesses value some things disproportionately highly compared to the trivial cost of it. There are plenty of reasons for this that he makes clear.

But that value is for that service, not a charity. It will never get redirected otherwise. So getting a business to happily pay a large sum for a cheap service is a fantastic way to ensure you now have the money to donate, and likely an order of magnitude more.

This is also the reason he says to charge $500 a month, but to give away the service to them that need it. Because the business is effectively subsidizing the needy here, while itself provably working in it's own interest. This is pretty win-win if anything.