"Same-sex relations... were generally acceptable in the Greco-Rman world, *especially if they were between socially unequal individuals*" - What does that mean?

"Same-sex relations... were generally acceptable in the Greco-Rman world, especially if they were between socially unequal individuals" - What does that mean?

by pokeaotic

Came across this line in my textbook - it was just an aside so not really important to the chapter, but I'm' curious what it means. I'm aware of the different mores they had in their culture regarding homosexual activities, but the different class thing threw me for a loop - I have no idea what it means.