I have written a lot, but I am afraid you may not have the patience to read through everything, so I try to keep it brief again: I think the organizers do not allow people to use AI, perhaps because they think that the AI on the market is basically created by training data with copyright disputes, so using these AI is infringing on copyright.
Although you mentioned no copyright, anti capitalism and no copyright are often not contradictory. You can see many capitalist companies using no copyright projects, or they themselves open source many AI models and projects.
But actually, I don't really care about copyright issues. Maybe it's because I'm a programmer, not an artist (you know). I think anti capitalism is more about expressing: there is no oppression of the people, no forced work of the people, no enslavement of the people, and so on. And the things you mentioned about private property and copyright, I think they have nothing to do with capitalism, they can also exist in other ideologies, such as socialism.