"Becoming"? Strength has been highly valued through pretty much all of human history. The extent of the exaltation has varied from time to time and place to place, but I ask you, how much did the Vikings value kindness or empathy? Or the Huns? Or the conquistadors and other European adventurers? Or the Aztecs, or the Atlantic slave traders, or the Comanches...and I could go on and on The truth of course is that none of those groups were monolithic, and they were all made up of varying individuals, some were probably wonderful people, some were assholes, just like today.
But the idea that all of a sudden people are obsessed with strength, as if they weren't before, is completely ahistorical.