>>42608230
It's just evangelist worldview. Even in the Middle Ages you could be semi-openly gay if you framed it right. "Brother-making" was a thing and especially adelphopoiesis was literally an orthodox rite where you gave your brother a big smack on the lips at the altar. Marriage in all but name. And if you go further back, just look at the greeks (lol).
Generally common (as in it showed up disproportionately often) among warrior castes and nobility all around in europe (as peasant you were shafted either way). Sure you might still be expected to continue your line, but love was usually secondary (or even irrelevant) compared to dynastic politics. Still, the influence wormed itself into later traditions or at least cultural imagination of warriors = male bonds beyond family.
>tfw Flash Magnus will never be your sworn brother