Baumer, I don't really think you're being fair towards the people who have issues with the film. You're basically playing the same song and dance you did with the ScarJo trans movie, and it's really disheartening to see you act like this.
I'm not gonna speak for everyone who is upset over this, but at least when it comes to Claire, who is in fact a Latina, I think she has the right to be upset. This is her culture, and she doesn't experience her culture through a lot of mainstream Hollywood films, so the idea that a movie based on a folklore legend from her own country has a Caucasian main character is a little bit disheartening for her, and she has the right to be upset about that.
Now it's true that the film isn't required to have a Hispanic lead as its character, but for a film based on a Mexican legend, wouldn't it make sense for the film to try and represent that side and have a Hispanic lead playing off of the monster? Just as an example, imagine if Black Panther, a film that seeped in African culture, Afrofuturism, and prided itself on black representation, did not have Chadwick Boseman as its lead, but a character played by Tom Hanks. Sure, the elements that made the film popular would be there, but the idea that a movie all about African culture would not have an actor of African descent be the leading part not only pushes back representation for black actors in being leads in their own movie, but also is disrespectful to the overall culture and would probably make many people of African descent unhappy and angry over the film.
And before you get into the whole "Well actors are just playing characters, they're just acting. Renee Zellwegger isn't British, so why is nobody upset over her playing Bridget Jones?" argument, let me tell you something about Latinos. They face oppression not just in political systems, but also in the film industry. White Europeans, or people of a European nationality do not face oppression. Latinos do, largely on the fact they have been marginalized for decades and because of systemic racism that holds them back from getting a lot of the same opportunities as white people do.
As an example, nowadays, there are several white actors that continuously get headline roles, from Leo to Pitt to Cooper to Bullock to Streep to Hanks to Cruise to McCarthy to Damon. When it comes to Latinos getting headline roles...well, Jennifer Lopez can still get some starring roles...Eugenio Derbez produces and stars in his own movies and has a niche fanbase that goes to see his movies a lot...and that's about it. If you want to be generous, there are actors like Benjamin Bratt, Salma Hayek and Edward James Olmos, but you don't see them in the front of the movie poster or get top billing all that much, at least in 2018. Hispanic representation in film is a major problem, to the point where a film about Mexican culture isn't having Mexican or at the very least Latino actors being the lead in these stories.
And before you go off about how "Well, there's not a lot of Latino actors that can lead a film" there in lies the problem. The Hollywood system, as much as it has tried to make up for its lack of diversity in the past, still hasn't offered a lot of opportunities for Latino actors, and this film would have been a great opportunity. Disregarding the cultural authenticity, this isn't a film that really needed a major actor headlining the film. The film's main pull is the titular monster, as well as James Wan as a producer. This already has so much going for it, so why not give the lead role to a woman who is a part of a historically underrepresented group, and have her represent a significant part of her own culture? And don't even bother trying to argue that Linda Cardellini is any big name. If the producers were able to give the lead role to an actress whose most famous film roles are Velma from Scooby-Doo and Mrs. Jeremy Renner in Age of Ultron, I think they can pass the same role to someone like Gina Rodriguez.
I'm not trying to say that this movie would automatically be better with a Latina replacing Cardellini. I don't even care about this movie whatsoever, and I probably wouldn't care about this movie regardless of who was cast. But if you're seriously gonna ignore the systemic racism Hollywood has, particularly with Hispanic actors, and think that chastising people for having issues with this film's casting is okay, especially when some of the people complaining are people who grew up with this culture, then quite honestly, you're being exceedingly disrespectful, pretty insensitive, and a little bit racist. I'm sure you didn't mean to come off that way, but that's how you're acting right now. Sorry.