You're right that if you're replicating an existing copyright image, the process doesn't matter. Legally, if you lived in a cave your whole life and never saw any art and by amazing coincidence you just happened to paint and sell the exact same painting as some other artist, you'd be violating their copyright. Independent creation doesn't protect you.
On the other hand, under current copyright law, if Stable Diffusion generates an original image that doesn't look like a copy of any existing image, it's clear the new image doesn't violate any artist's copyright.
The debate is whether you can use copyright images/text to train an AI.
Stable Diffusion is of course trained on millions of photos of the real world, in addition to images made by artists. Of course, humans artists also see and digest both the real world and images by other artists and both influence their output. That's why you get trends like impressionism.
On the other hand, under current copyright law, if Stable Diffusion generates an original image that doesn't look like a copy of any existing image, it's clear the new image doesn't violate any artist's copyright.
The debate is whether you can use copyright images/text to train an AI.
Stable Diffusion is of course trained on millions of photos of the real world, in addition to images made by artists. Of course, humans artists also see and digest both the real world and images by other artists and both influence their output. That's why you get trends like impressionism.