I'm curious about the details, yeah. Maybe they're plugging into some API or something? Breaking some safety measure? Otherwise I really don't see how these threats aren't empty. Suing somebody for breaking EULA terms does not have a great track record, and neither does modifying things you buy or making unauthorized software for computers.
But hey, if the guy says the project is coming down, then I guess the aggressive language did the thing they wanted it to do, even if it's relatively toothless.