That would be a good point, except... No one is talking about the characters, the cast or even the movie itself...
People are discussing the film's failure and what said failure means to the superhero genre, to Hollywood and (more specifically) to Disney. Because it's by far the biggest flop of the world's biggest movie franchise, which happens to belong to the world's biggest (?) entertainment industry.
No one cares about The Marvels (characters or cast), just about its failure.
I'm sure Hollywood and media personality will still still use the good ol' "everyone is a bigot" excuse that Hollywood loves so much (the director already did)... But I think public losing interest in a franchise that has only produced flops in the last 4 years is a much more likely explanation than "everyone is a bigot". Especially considering the recent history of Marvel movies (and the superhero genre in general) and just how bad of a flop The Marvels is (worst ever Marvel opening and a 87% drop in audience by the 2nd weekend. - Is Captain Marvel hated by the whole country (especially by women, since 65% of the audience is male)?