It is frequently difficult to imagine social structures that are utterly contrary to what we know today. When I speak, what shocks people is the history of human sexuality that they are completely unaware of.
The simple answer is research. It is quite simple to see the patterns when reading various sources. I would direct you to a carefully built foundation I construct in Chapters 1 and 2 of my book Walking the Bridgeless Canyon. You might challenge yourself and try to find male-male relationships before the middle of the 19th century that did not involve age and/or power differentials.
The first recorded consideration of a man’s role in sex as opposed to his natural attraction was in a letter between Karl Kertbeny and Karl Urichs in 1868. As I stated in the video, it took another four plus decades until role verses attraction made its way into a concept in the culture.
Though the division line is a bit amorphic, without doubt, before the late 19th century, a man who took the role of the one being penetrated was seen to be taking the role of a woman — a devalued place both socially and sexually. Penetrated men were typically boys (usually sub-20 year old) or, depending on the time in history, a slave, a prostitute, one subjugated in war, or of a far lower class. Equal status, same-sex relationships between men were unacceptable.
If you care to do more extensive research on your own, I also suggest: The Construction of Homosexuality by David Greenberg, Bible Gender Sexuality by Dr. James Brownson, the opening chapters of Gay New York by George Chauncey, The Invention of Heterosexuality by Jonathan Ned Katz, and The Body and Society by Peter Brown.
There is abundant information to substantiate this concept. I summarize it in my book.
The same person also asked: You say, “Any time in history, men could basically do whatever they want with their bodies as long as they play the role of the penetrator… boy, animal, man, woman… so long as the man is acting as the penetrator everything is fine in mainland.”According to who? Who thought this? Certainly not Christians! Obviously there may be instances of these types of sexual activities, but they were viewed as corrupt and certainly not “fine in mainland”.
You are absolutely correct that this form of sexual use and abuse was not approved of within Christianity, but it was common in the cultures in biblical times. It is precisely this common use and abuse of women, boys, men of lower status that is addressed. Using others is the sin. Selling and sexually using others is the sin. Subjugating others is the sin. It is difficult to directly understand the “sin” of using a man as one would a woman when, in our culture, the worst thing to be in not a woman.
Again, the same sources listed above will be a strong case for this concept for the only acceptable role in sex for men — the penetrator.