they didn't sue him for programming without a license but for DMCA and copyright violations.
That's true in the same technical sense that Denys Vlasenko sues violators of the BusyBox license not for "GPL violation" but instead for copyright infringement. If the only way to program without a license is to violate Title 17, then in practice that's the same thing as banning "programming without a license".
Sony had a simple rule "If you follow these rules you can play in our sandbox"
One of the rules at the time was not to use hardware that was still being produced. The fat PS3 had been discontinued in favor of a new model without Other OS support. Assuming hypothetically that George Hotz had not exposed PS3 flaws to give Sony cause to disable Other OS in 3.21, where would one find a replacement for a fat PS3 console whose hardware had failed?