Instructors and art books literally give permission to use them as a "stepping stone" by definition. The entire point of them is to offer input to other artists.

Also the main difference is that a human has a human mind and is making creative decisions unique to that human. The problem is that a narrow AI algorithm cannot be anything BUT derivative. They don't think, they don't have a mind that filters the data through a unique perspective, they just process the data like a series of conveyer belts. If you never give a human any input from other artists they can still make art, that's why we have cave paintings. But a narrow AI algorithm needs specific input via specific pieces of art or else it can't create anything. With that in mind permission and consent is much more important to the artists whose specific pieces are being fed into the algorithm. It's generally considered good form to credit inspiration in derivative work, but we understand that human nature means that humans may not always remember or realize what or who inspired them. AI doesn't have that excuse. We are perfectly capable of only feeding images that we are given permission to use into AI, and we are perfectly capable of having the AI log and report what works it used data from.