If you really understand music theory, you'll see that it's a science, with math at its core. The art is in how the science is applied.
If a painter forgets the color wheel, they won't be able to mix colors to get what they want. They'll wind up with a bunch of browns when they wanted greens and purples. If they forget the fundamentals like lines and forms and negative space, they'll end up with shapeless blobs.
I mean I guess some people like abstract art, and that's fine. But let's not pretend music theory is just some relic of colonialism. It isn't eurocentric to believe harmonious and rhythmic music sounds better than music that isn't.