I've lived in the US all my life and I've never found any of that to be even a little bit true.
i've lived in the US my entire life and i've found it extremely true, though granted i've found it extremely true anecdotally because it's largely one of those things that IMO is like how "anti-abortion people don't care about life, they care about controlling women" is true even though i don't know i could prove it to a standard of scientific scrutiny.
anyways...
obviously our culture pays lip service to the idea that bullying is bad, but if you look at the reality behind how we treat the existence of bullying it proves the lie.
what do we say about bullying? "ignore them and they'll go away" or "don't stoop to their level" or "just go tell an adult" - the narrative about bullying is always about how to respond to it, how to passively defend yourself or how to retreat and beg a higher authority to intervene.
(excepting the single "punch 'em in the nose" cliche but even that is always shown as a radical notion outside of the bounds of accepted behavior)
the narrative in the US is *never* about what a piece of shit you are for bullying and how being an asshole is socially intolerable.
the lessons and the lectures are never about framing life within civilization about cooperation and tolerance, it's always about "well boys will be boys what can ya do"
we love the idea that the scrappy underdog will stand up and take a swing at their oppressors, but the reality is that if you do that what ends up happening is you get suspended for a week for fighting and the kid who was harassing you for 3 months leading up to that is told "oh now be nice" and otherwise left alone.