Earlier quoted context omitted.
I fail to see the difference between "underlying structure" and "short-range visual features". Both are just simple statistical relationships between parameters and random variables.
Sure, but why would that not apply to humans? And we don't consider it copyright violation if a human learns painting by looking at art.
Most human behavior is easy to describe with only a few underlying parameters, but there are outlier behaviors where the number of parameters grows unboundedly.
("AI" hasn't even come close to modeling these outliers.)
Internet pictures squarely falls into the "few underlying parameters" bucket.