I don't care much for what laws say. If the only way someones service can work is by ingesting the work of someone else, without compensation, and then compete

I don't care much for what laws say. If the only way someones service can work is by ingesting the work of someone else, without compensation, and then compete with that same person, that is wrong. If a company reverse engineers a competitors product, they still buy the product to tear it apart and figure out how it works. If a student learns from their teacher, then goes on to sell a similar kind of work as what their teacher makes, at least the student paid for the classes. This arrangement offers none of that. As long as theft is illegal, this should be. I'd call it parasitic, but it isn't; this is a parasite who's sole intent is to kill the host.