Every kind of property is imaginary. Yes, physical property has an element of physical possession, but that's not enough legal infrastructure to, say, rent that property out for a recurring fee that must be paid on pain of eviction or repossession. All of that has to be enforced by violence dealt by the state, which renders it just as "imaginary" as the copyright laws that are also backed purely by the fact that the state allows authors to call down the full force of the US government on people that infringe their copyright.

What you are mad about is not imaginary-ness, but centralization[0]. Any critique of law should be done on this yardstick - i.e. is that law protecting the interests of the many, or the few?

In prior decades, ordinary people did not have to care about copyright law, which is why the bargain was tolerable then: copyright took money out of the pockets of the few (publishers) and gave it to the many (authors). But now that publishers figured out how to buy up all the valuable assets and you can practically enforce copyright on individuals, the system has changed to one that takes money from the people at-large and puts it in the pockets of about four publishers. On that basis alone you can argue for abolishing copyright[1] because it no longer serves the interests of the public.

Now, let's look at the business model of AI companies. AI compute is hideously expensive, and so every company involved is already a highly centralized tech monopoly. And with only a few exceptions the largest models are all jealously protected trade secrets you're only allowed to access through heavily monitored APIs. Models with published weights do exist, but they are invariably either too big to run on most hardware or lag in capability and performance. The practical fact of the matter is that most people will use AI - even open models - through inferencing servers ultimately owned by tech monopolies. This is a deeply, incredibly centralizing force.

And, unlike copyright, trade secrecy is one of those few IP laws[2] that aren't completely imaginary. It's rooted in possession, just like physical property rights are. The "no imaginary rights" argument still gets us horrible tech monopolies that can censor or marginalize you.

[0] aka "wealth inequality"

[1] What you replace it with is a separate question, but again, Benn Jordan wants socialized ownership.

[2] "Laws that allow you to dictate the conduct of your competitors"

But that's precisely the problem—while in theory the ideal is good, it is impractical unless you fundamentally change the economic model.

Artists rely on some form of IP to help secure payment for their creative works. They need this payment to be able to afford their own subsistence so that they can continue to live and create.

In an alternative system, maybe you could abolish all forms of IP outright, but how will you do that under capitalism while sustaining (already impoverished) artists?

If you are against the principle of IP, you are essentially saying that an entire segment of capital should be deactivated, and effectively the only jobs remaining would be those of active service/tangible goods. In the age of digital media, basically everything is instantly and infinitely replicable, so you are effectively asking for a world in which it becomes rapidly impossible to make money off of any kind of digital good (music, literature, film, software, etc.) This has an obvious material consequence of disincentivizing creation of these works simply because if the creators need to earn wages in tangible good/service markets they have strictly less time to devote to the creation of creative works.