You don't write books about things you don't think.
You don't think about things that are obvious.
Things are not obvious if they make you hesitate.
You don't hesitate if nobody doubts your way.
Nobody doubts your way if they everybody is the same.
In conclusion, I'm sure homophobia is not a 20th century phenomenon and they were rationalizing copulation with no chance of reproduction. They were educated men, after all, and knew that no babies were made.
Yes, I'm yanking your chain.
No, I got nothing against homosexuals.
I'm saying they liked to hump anything that moved and probably even things that didn't in ancient Greece. That fact reflected on the texts produced in that time and the science of thinking got a bit stuck in the sex part. I guess not that much has changed since then but at least we try to separate thinking from thinking just sex.