Take this with a bucket of salt because I haven't read much on this topic.

But just reasoning 'rationally', I assume the argument is that the Iliad / Oddysey were told in cultures of predominantly oral tradition? So likely, just as with the game of telephone, the story got told and retold, and distorted, many times until someone ("Homer") decided to write it down?

So the argument being that Homer is not the 'creator' of the stories, and might just be someone who wrote it down?

Or perhaps the argument is that no single person wrote it down?