It is funny because if you know too much history you will roll your eyes at Adastra. But if you know just bits and pieces you can appreciate and understand some of the culture.
In ancient Rome, like in Adastra, it was socially acceptable for m/m sex. Who knows why. Maybe it was an accepted fetish to humiliate another straight person that way or if it was just friends helping each other release some steam. History doesnt know why but it was just socially acceptable. But ACTUALLY having a male lover as a male was looked down upon just as it is in Adastra. And like in Adastra an emperor shouldn't be the 'bottom'. / In short, when Rome conquered Greece it was actually Greek culture that ended up dominating Roman culture, especially within higher society. As you also might know, the Romans adopted the Greek gods but changed their names (to the planet names we are familiar with). And like us today, they may have changed the names of certain celebrations but the topics stayed the same, some of which were plain our orgies.
When Christianity came around it was an antithesis religion or slave religion as some philosophers call it. Because the slave cannot have glory, comfort, sex, and other things the masters took for granted, they viewed those as sin and said what makes you holy is temperance, fasting, abstinence, and so on. If you have looked at the passage of a man shall not lay with another man in the original language they use different words to describe "man". A more accurate translation would be no adult shall lay with a adolescent. This is because back then it was quite normal for 12-18 year olds to be with 20-40 year olds in a m/m relationship especially when away from their wives on long trips (cuz apparently gay sex with a substantial age difference doesnt count as cheating on your wife). Peculiar, and almost a traumatizing experience I bet for most adolescents these days, but whatever I guess.