Yeah, I think his ideological commitment to "all intellectual property rights are bad forever and always amen" kind of blinds him to the actual issue here, and his proposed solution is kind of nonsensical in terms of its ability to get off the ground.

More broadly, (ie not just in relation to Cory Doctorow), I've seen the take floating around that's like "hey, what the heck, artists who were opposed to ridiculous IP rights restrictions when it was the music industry doing it are now in favor of those restrictions when it's AI, what gives with this hypocrisy?" which I think kind of... misses the point?

A lot of artists generally are in favor of using their work for interesting collaborative stuff and aren't going to get mad if you use their stuff for your own creative endeavors. This is why we have things like Creative Commons. The actual things artists tend not to like are things like having their work used for commercial purposes without permission and/or having their work taken without credit. (This is why CC licenses often restrict these usages!) With that in mind, a lot of the artist outrage over AI feels much more in line with artists getting mad about, say, watermark-removal tools, or people reposting art without credit, than it does with the copyright battles of the 00s. (You may remember one of the big things artists were affronted by about AI art was the way it would imitate an artist's signature, because of what that represented.)

In this case, artists are leaning on copyright not out of any particular ideological commitment but just because it's the blunt instrument that they already have at their disposal. But I think Cory Doctorow's previous experience in "getting mad at the MPAA" or whatever kind of forces him to analyze this using the same framing as that issue, which doesn't really make sense in this case. And ironically saying "copyright shouldn't count for AI" aligns him with the position of the MPAA so it really does feel like a "live long enough to see yourself become the villain" scenario. :/