No, the way things are represented does matter. Whether you like it or not, whether you think so or not, everything you see influences you. It can give negative and positive views for certain things. If you only see a certain group of people having only negative representation, regardless if you realize they’re individuals, you’re going to associate negative traits with people of those backgrounds. People who have a negative view of a particular group of people may not be explicitly yelling, or being violent, but that doesn’t mean people aren’t going to be effected by biases instilled in them from media when talking to, interacting, and considering people of that group.
To put it on an individual level, let’s say you have a friend who has a person they work with that they do not like. You’ve never met this person, but from what you hear about them from your friend, they seem to have a really bad attitude. You’ve never heard anything good about them. You realize that your friend clearly has a negative view of them, but you could meet this person and go in with the expectation of a negative experience, because all you know about them is negative things. But you might realize that they’re nothing like how your friend has portrayed them, does that make your friend a liar? No, their experience is still there, but it doesn’t mean that they’re being dubious and trying to trick you into thinking they’re not a bad person. They’re just someone who doesn’t get along with someone else that you happen to know. Thoughts are easily influenced and while there are people who can easily identify these influences and try to disregard them, it’s not something everyone does.
Yes, but why make it easier for them to justify it by representing a group only or mostly in a bad light? Every group is gonna have good and bad people, but why should we choose certain groups to be portrayed as ‘bad,’ when we can just portray people as bad. Like you mentioned with filling in the blank earlier, media likes to do that with “this person is bad because of [one singular trait], while this person is good because of [an opposing trait to the bad person’s trait].” Of course not every piece of media is like that, but a lot of media does tend to have a strict dichotomy of good and bad.
Hell, I remember years ago Markiplier talking about how he wanted to get into acting and talking about how he needed to redye his hair to a more natural color as characters with dyed hair tend to have a narrow set of traits that aren’t necessarily ‘good’ traits, and that’s not the type of role he wanted. I forget the exact words he used, but it showed that even physical attributes such as hair have their own sort of stereotypes within media. We even see this today with actual people, when someone wants to talk about “woke” people, they often act like they have dyed hair (I think specifically blue for some reason), have piercings, tattoos, and other ‘non-traditional’ ways that that person has decided to express themselves.
And I’m not trying to dismiss your life experiences, I don’t doubt that there are Navajo people don’t care about non-Navajo people talking about and using skinwalkers in media. But just because something is being represented doesn’t mean it’s being done with respect, and some of us want to be considerate to those who may find it disrespectful and harmful to how outsiders perceive them.