First, think about when you see something in film that doesn’t make sense. For example, the final season of Game of Thrones when Danerys goes bonkers out of nowhere. Everyone thought that made no sense because in their own lives, personality is generally stable. People don’t go from being altruistic to genocidal because of a bell. Watchers then blamed the producers for making a terrible decision with the season due to ulterior personal motives.
Think about what a racist’s life looks like. What do their social environments look like? They likely only have a few people of color (PoC) around if any. They may have interactions with PoC at work, but since work is somewhat of a forced experience because their coworkers were chosen by someone else, that’s what interactions there feel like: imposed. So to them, life is a bunch of a White people and PoC are impositions. This is reality for them.
When they see a movie that doesn’t reflect their reality, they notice it and try to make sense of it. Applying what their reality is, they see the PoC as being imposed. The right-wing media then plays off of this and tells them that it’s because a progressive boogeyman is trying to make reality different for nefarious purposes. Progressive people are blamed for their discomfort and so it goes.