Musk should sue for DDoS if the TOS don't allow massive scraping. He should also sue to explore the general legality of the AI racket, because copyright was made for humans and everyone on Twitter has posted under that assumption.
Yes, it is ethical. In many countries it is legal for humans to walk around the public square and overhear all conversations.
It is NOT legal to install cameras that record everyone's conversations, much less sell the laundered results.
Pre-2023 people went on Twitter with the expectation that their output would be read by humans.
A traditional search engine is different: It redirects to the original. A bastardized search engine that shows snippets is more questionable, but still miles away from the AI steal.
Many countries have freedom of panorama, which means it is legal to video record the public square. I'm not aware if anywhere has specific laws on mounting the camera on a robot.
