This is not just about copyright infringement or plagiarism.
Automatically generating text, images and videos based on training data and a tiny prompt is fundamentally about taking someone's work and making money off of it without giving anything in return.
No matter what text you put in the prompt you'll get /something/. Just because you put "studio ghibli anime" in the prompt doesn't mean you're going to actually get that out of it. It'll just be kind of yellow and blobby.
(Also, the style isn't from "people" but a specific guy named Yoshifumi Kondo who isn't around anymore.)
Though… I'm always surprised how respectful Westerners are about Miyazaki. Meanwhile you read other Japanese directors and they're saying all kinds of things about him.