I think you honestly haven't a clue what you're talking about. The movie has one racist character that I can recall, and he's portrayed as a vile ******* with no friends who is ultimately killed for his bigoted beliefs.
Douglas' character is not racist. He even learns how to fire the rocket from a little black kid. He is simply a psychopath who has never been in touch with reality and sees how oblivious he's been all along when he watches his home movies which he remembers very differently. It's why he decides to let himself be killed. He sees that he is what he's been raging against all day.
Duvall? Def not a racist. Has a partner/protege that is Hispanic and he likes very much.
As to others believing it, well, a lot of people also believe Jesus will be back any day now.