Based on their belief/illusion, they have prohibited marriage and romance between two races.
|People act based on their recognition. The Rounds who recognised Triangles as an inferior race subsequently prohibited romance and marriage between the Rounds and the Triangles. It is because making a baby with an inferior race goes against the evolution of humans.|
|N.B. This is not related to Jim Crow laws / Prohibition of Mixed Marriages Act / Immorality Act on this earth.|