Computers aren't people. Software isn't humans.
This is different to most copyright cases where all that matters is the end result, not the process.
As others have already mentioned here before:
- a "style" isn't copyright-able
- Looking at how others have done art, imitating them to learn, and then combining what we learned with everything else we've seen in our life is how humans produce art. And it's the same way that stablediffusion produces art: train on data, reproduce based on what it's learned, combine everything its seen with a prompt to create something new.