Opposing arguments are like this one, also quoted from the Washington Post article above:

"generative AI typically produces content only in response to prompts or queries from a user; these responses could be seen as simply remixing content from the third-party websites, whose data it was trained on"

If you are taking that broad a definition of "it's just a remix" then buddy, I have news for you about literally all creativity, language, and culture. By that logic, no one is liable for anything