Does it portray how Baum advocated extermination of all native Americans

There is much debate on whether or not he was actually for the extermination of the American Indian. If you take the editorials at face value then yes, it looks like he is for it but if you look at it as a man using extreme views to show how stupid that thinking is then it doesn't.

That would have to be a different movie. This one was about how he came to write The Wizard of Oz, nothing more.

It's funny how people want every aspect of a person's life injected into a 2-hour biopic. Two years ago, some were dismayed that Walt Disney's alleged antisemitism and his turning over accused Communists weren't mentioned in Saving Mr. Banks, but that movie was about the pre-production of Mary Poppins. Plus, Walt only has a supporting role in that movie, which is mainly about P.L. Travers and her inspiration(s) for Mary Poppins.

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