Isn't this similar to how every single piece of art is created? You look at bunch of propriety art, copy it to learn how to create it yourself (just for learning, not to sell those copies), eventually learn enough to start being able to create art from scratch and then start selling your unique art?
Would watching a lot of animated movies in order to learn how to create good animated movies yourself be unethical as well?
No, it's not. Art created by humans is not just looking at other art and trying to copy it. It's a culmination of a whole life of experiences and the personality of the artist. Looking at other peoples art is inspiration and useful for learning technique, but only a very small part of the bigger picture.
Presumably, if the ethics in question includes not leaving entire classes of skilled workers worldwide to hang like the States left its autoworkers hanging after the 70s - yes.
Would watching a lot of animated movies in order to learn how to create good animated movies yourself be unethical as well?