While you live in the states, you're surrounded by it. It's aggressively pushed from everywhere. You can't resist, because disobedience will likely cause harm to you (e.g. losing a job and failure to pay the mortgage).
So you naturally start to believe that it's all true and justified and the only way. I get it.
But if you're outside of your society, outside of the pressure of making everyone accept this, it looks weird, even deranged in many cases. I'm pretty sure it causes and will cause loss of sales outside of the US. It would be carefully hidden and hard to prove, but I don't have to prove it. E.g. I just know that nobody from my friends and family would like to watch such a movie. Yeah, we discuss it and the opinion is pretty much universal among my family, my friends, my coworkers.
It's even hard to understand it because we were not involved in the slave trade. And we really can't understand what problems experienced and continue to experience black people in the USA. This is true, but while it is hard to understand, it's much more easier to understand that making them play main roles in historical movies doesn't repair any injustices made to them.