And even a massive chunk of European aggressive anti-homosexuality comes from the 19th century nation-building era, where statesmen became concerned about the masculinity of their states. It is easy to blame this shit on Christianity, but as anyone who has actually read the biblical evidence can see how it's a minor rule drawn from a chapter that also includes instructions for how God likes his meat cooked and rules about how to build separate housing for women on their menses. Historically, from what I can tell, the medieval world used Homosexuality as a sort of legislative insult, like something you'd tack on to the real charges in order to make the accused look bad. A sort of "You embezzled funds from the church, and you are also fuckin' GAY!"

This isn't to say homosexuality was as acceptable as it would have been to the ancient Greeks, but rather that so long as it wasn't out in public people would general be OK with it being a rumor. There would be exceptions, but they would always be tied to something else, even if that something else was just a grudge.

Until you get to the Enlightenment. It is easy to think of the Enlightenment as the time where human rights were first popularized and science ruled supreme, but it was also a time when cold machine-thinking was admired and pseudo-science ruled the popular imagination. Its easier to imagine homosexuality as some sort of disease when you are actually in the practice of classifying diseases, and the new Darwinian and Malthusian concern about how population worked brought social deviation to the spotlight, and made it something that was damned by leaders who wanted to develop the manliest populations of modern soldiers that they could. After all, they needed to breed all those guys who would die in the trenches in 1914.