Why is it actually different?

If I study a painting (train a model) and then replicate the style am I stealing the painting off of an artist?

If I illegally obtained a copy of the painting that i studied, would the piece that I generated belong to the artist of the painting i studied?

If I go to a wine and design thing and paint a picture after being instructed how and following specifically with a template, does that make my painting no longer mine?

Is a person sitting in a free museum sketching in their notebook, a version of the painting that they see on the wall stealing?

Ai is not copying, the work that it generates is novel. The training data may have been obtained illegally (debatable and not settled in law) but that doesn’t make the generated work any less new or novel.

In your own example, the people who 'went to school and learned from the masters" also don’t pay the original artists. Art students aren’t paying the Gogh estate for permission to study his paintings and they aren’t paying royalties for making something that looks and feels like his paintings either.