You don't have to follow USA rules unless you do business within USA.
The key point is that doing fully digital business online (as opposed to selling physical goods online to people within your country) doesn't mean that no jurisdiction applies, it means that all of them do - if you do international trade with USA, then you have to be mindful of USA laws.
When I (located in USA) buy physical product from other country - it is my responsibility to import it properly. But somehow digital services put burden for following USA countries on foreign entities.
The key point is that doing fully digital business online (as opposed to selling physical goods online to people within your country) doesn't mean that no jurisdiction applies, it means that all of them do - if you do international trade with USA, then you have to be mindful of USA laws.