Okay, the misinformation is getting a little out of hand here. DigitalOcean certainly aren't charging you to erase your data, all you have to do is check the "Scrub Data" checkbox. Yes, you have to pay for the time your VPS is on while erasing, but that's perfectly reasonable.
Why would that be perfectly reasonable? They have an obligation to not make my data available to other people, I don't give a rats ass about the technical details of doing that.
It's called a dark pattern.