Where did you read that it is an excuse? I seem to remind that I explicitly worded it like a problem that (some) AI art has. It is not better (morally) than tracing.
If you were to outsource your art commission to a sweatshop, the artists that people want to protect from AI would still not have your commisions. Even better (actually, worse), if people condemn AI art, there would be more of an incentive to have such sweatshops, just to be able to tell, a human made it. You see similar evasions how companies try to get a label of Made in Country or for food , where they do one tiny step in production to be able to tell that the meat is locally made.
Against some AI one can argue with the trainging methods, similar to tracing, but those arguments would not hold for other AI concepts. The fact that you use mass production to put people out of jobs never worked as an argument in the past. There need to be better arguments against AI.