No more "malicious" than raising a price.
Furthermore, by framing it that way, you're being disingenuous about what exactly is "the program" that ceases functioning. In the scenario where the program is on Github, you're making the new version of the program cease to function, but the old version still functions, and the user is still permitted to use it--that is, the real problem isn't that "the program" ceases to function, but that you're replacing a still functioning version by a nonfunctioning one automatically. In the scenario where you're charging $10000, there is, in actual practice, no old functioning version.
In a weird scenario which was closer (but which doesn't happen much in practice), charging $10000 would be objectionable too.
That's funny. I don't remember reading about a backdoor he installed. Do you have a link?
Or are you blaming him for the fact that people kept downloading his repo's package after he told them to stop?
I think his behavior was petty and amateurish, but it also only had a negative impact because people were still loading his package directly instead of forking it like he advised in November.
(Note: I don't blame GitHub at all. He burned his bridges with them quite intentionally, and in the process made their continued relationship with him a huge problem for their customers. I don't see what other option they had, to be honest.)