I think the connection isn't with belief in the supernatural, but with the specific belief that there are things around us that look like people but aren't people. I can easily see how the latter at minimum makes one very susceptible for racism.
If people start believing that androids are a real thing (not the OS, human like robots), it's only a matter of time before people will be accused of being androids.
Why is it art from artists who made their last work in 1912? Modern copyright lasts life plus X, where X has been increasing and is now mostly 70, though some stopped at 50. So why 1912? Did US copyright change that year?