Turn it around, though: if Google feels like it's not responsible for anything it hosts, shouldn't it say so, loud and clear? Say, a banner that says, "Hey, we'll delete your stuff any time we feel like it," at the top of every Gmail page?
Google's users aren't parasites. There is both a relationship and an exchange of economic value. That's why Google has worked very hard to be trusted by everybody, to be seen as responsible stewards of vast amounts of often very personal information.
If Google doesn't want people to trust them, they should not work so hard to be seen as trustworthy. That the artist believed them is not an error on his part.
Typing out words on a forum and hitting "reply" is easy regardless whether you support the victim or not. Don't see your point?
Sure, the TOS says "we can delete it whenever"/"no promises", but the advertising and general pitching of the product have heavily indicated otherwise. I don't see the service going away, and when you have so much identity tied to your email, it's pretty shocking to realize that it could all disappear in a flash.
If Google were to kill my email accounts, I would be _seriously_ disadvantaged.
Saying that only fools trust Google to keep your things forever is true, but also lacks empathy.
Sure, he's not paying, but Google doesn't ask for payment. They provide a service which is backed by Google's implicit guarantee that their web hosting is safe and reliable, and they've broken that guarantee. Google may not have a legal responsibility to not delete everything this artist made, but every time something like this happens, the rest of us should notice it and reconsider whether Google is a good platform to trust with our work.
If the internet didn't exist, an artist would have bought storage for his art. Why this artist feels that a service he didn't pay for owes him anything is baffling to me.