The difference surely is that Bob scrapes the knife, not Bob instructs the knife to scrape paint?
When using a wacom tablet, using the pencil tool in photoshop is very similar to using a pencil. You're "instructing" the pencil tool to move by moving the pencil controller with respect to the tablet.
I know AI slop art when I see it, and I have no interest it making or "consuming" it. But I don't think I could construct a robust definition that would stand up to adversarial scrutiny.