The Irish-descended in the Northeast USA are like that. It's also linked to proximity imho. Confined to similar cramped urban spaces and forced to compete and then one of them ends up on the White List and suddenly they can lord over the other minorities like its a chip on the shoulder.

My dear friend who is from Mexico has educated me on the kind of racism there and its similar to the kind you find up here. Add the Catholic cultural conservatism and especially machismo/misogynist cultural aspects and you're primed to be more aligned with the dominant trends of white supremacy than you are with the racial situation.

Also as others have pointed out: whiteness isn't real, it's a social construct that expands or contracts based on the situation necessary for the bourgeoisie to maintain control. Remember the Night of the Long Knives. They'll bring you into the fold until it is politically expedient to exclude you.