1. Proprietary software is harmful and immoral in ways that proprietary books or movies are not.
2. The creative industry has historically used copyright as a tool to tell computer programmers to stop having fun.
So the lack of empathy is actually pretty predictable. Artists - or at least, the people who claim to represent their economic interests - have consistently used copyright as a cudgel to smack programmers about. If you've been marinading in Free Software culture and Cory Doctorow-grade ressentiment for half a century, you're going to be more interested in taking revenge against the people who have been telling you "No, shut up, that's communism" than mere first-order self-preservation[1].
This isn't just "programmers don't have fucks to give", though. In fact, your actual statements about computer programmers are wrong, because there's already an active lawsuit against OpenAI and Microsoft over GitHub Copilot and it's use of FOSS code.
You see, AI actually breaks the copyright and ethical norms of programmers, too. Most public code happens to be licensed under terms that permit reuse (we hate copyright), but only if derivatives and modifications are also shared in the same manner (because we really hate copyright). Artists are worried about being paid, but programmers are worried about keeping the commons open. The former is easy: OpenAI can offer a rev share for people whose images were in the training set. The latter is far harder, because OpenAI's business model is charging people for access to the AI. We don't want to be paid, we want OpenAI to not be paid.
Also, the assumption that "art is more difficult than computer programming" is also hilariously devoid of empathy. For every junior programmer crudly duck-taping code together you have a person drawing MS Paint fanart on their DeviantART page. The two fields test different skills and you cannot just say one is harder than the other. Furthermore, the consequences are different here. If art is bad, it's bad[0] and people potentially lose money; but if code is bad it gets hacked or kills people.
[0] I am intentionally not going to mention the concerns Stability AI has with people generating CSAM with AI art generators. That's an entirely different can of worms.
[1] Revenge can itself be thought of as a second-order self-preservation strategy (i.e. you hurt me, so I'd better hurt you so that you can't hurt me twice).