I think you are focusing on the wrong questions.
1. Do you believe harming humans is bad?
2. Would you choose to eat them if they taste just like chicken?
Perhaps the reason you choose not to eat humans is because it is illegal and is punishable to kill humans for food whereas killing animals for food is still acceptable in society. And hence it is an easy low hanging moralistic fruit to be vegan.
It is also likely that you might be harmed if you consume human flesh.(Hello, prions!) There are multiple deterrents to becoming a cannibal vs eating like a non vegan.
You haven’t made a moral choice at all when you consume animal flesh while still believing that harming animals is bad. Just like you haven’t made a moral choice at all when you appropriate other artists’ work without their consent. There is no ‘moral choice’ made here because you chose not to choose when there is no stick to be afraid of..
The only reason why it would be easy for AI art to exist is because it is not punishable. There is no law against it.
In other words, people will continue indulging in their whims as long as there is no stick to punish them.
Your thought?