Among the goals seems to be a bit of well-poisoning. Artists have done this previously by creating art saying, say, "This site sells STOLEN artwork, do NOT by from them", and encouraging followers to reply with "I want this on a t-shirt", which had previously been used by rip-off sites to pirate artwork. See:

<https://waxy.org/2019/12/how-artists-on-twitter-tricked-spam...>

If art streams are tree-spiked with copyrighted or trademarked works, then AI generators might be a bit more gun-shy about training with abandon on such threads.

It's a form of monkeywrenching.

<https://en.wikipedia.org/wiki/Tree_spiking>

<https://en.wikipedia.org/wiki/Sabotage#As_environmental_acti...>