The allowance for copyright law to exist in the USA is "To promote the Progress of Science and useful Arts"; with a similar intent to patents to eventually bring more quality things into the public domain. So yes, anything outside of that, regardless of invention of non-science/useful-arts, and regardless of profitability, is fair game.

Any other enforcements and punishments are overreaches by government on behalf of lobbying. Many agree that the scope and punishments on the books in the USA far outweigh the punished behavior, and these are being foisted upon the rest of the world in strong-armed multinational agreements, against the will of the people on the receiving ends.