okay. how do I explain this.
the billions and billions of dollars the united states military pours into securing favorable depictions in popular media is the teeny tiniest little tip of the iceberg. a marvel movie is not the first or only place that most americans are encountering military propaganda. I cannot emphasize enough that the average americans grow up in an environment where the lionization of the military is the absolute default stance and even lightly questioning this state of affairs is considered an extreme radical stance. unquestioned obeisance to the military and the notion that the united states' imperial war machine is somehow "protecting our rights" by occupying and terrorizing countless foreign countries, is taught from childhood, not simply by media (although, yes, also there) but by our families, teachers, and social and political institutions.
the same simply cannot be said of incest shipping or mafia romance or whatever the fuck you're on about, and this is an extremely weak comparison to make. I would, actually, argue that a lot of the sexualized violence found in heterosexual "dark romance" is in fact a logical extension of the misogyny and casual violence towards women that's already extremely normalized in many heterosexual relationships and has already been socially acceptable for thousands of years, rather than the cause you seem to think it is.