No, it's not. A better comparison would be a poem that feels the same as an existing one and using the same prose but with its own words. Or any musical plagiarism dispute where the song is clearly different but similar enough that it needs to be decided by court. ChatGPT is not just copypasting a puzzle game here.
Only a small percentage of our output is unique/original, otherwise we live to produce very similar output to what we've had as input.
Common phrases, hell all languages are examples of this. Mimicry of behaviours; it's literally the learning process that evolution gave us that puts us (and other animals) above much simpler creatures.
GPT isn't perfect, but it's like a dog observing that you fetch the newspaper every morning and then it starts fetching it itself for you, then the neighbour is like "well, it's not _originaaal_".