I have heard that pink/blue used to have completely the opposite gender connotations. Pink was seen as a form of red, which was a strong/masculine colour. Blue was seen as delicate and ladylike, like an eggshell (whichever bird it is that lays blue eggs, I mean that kind of eggshell)

Now it’s all different… which is why it’s no longer manly to wear pink. “Manly” being a social construct, it’s defined by the current norms, and currently the norm is that pink is for little girls. Little girls are very, very rarely manly, so by extension pink is also not manly.

Tell you what outlasts social norms in terms of manliness… real men wear the blood of their enemies. That never goes out of manliness.