Wow. I always wondered what "the kiss of death" meant. Well I feel a lot better knowing that those Corleone boys weren't homos. Thanks for the education.
The Mafia was a family. It is literally “A FAMILY”. The Godfather is literally everyones GODFATHER.The relationships were very close. It was so tight, that betrayal is treated like you hurt a member of the family. When a superior kisses a person in the family(only one his own), it meant to represent The betrayal of Judas against Christ. Thats where it originated from .It was done in many cultures . Upon seeing the very public kiss, everyone knew that person was next to die without talking about it. They were marked.
Oh ...and the person who was kissed knows they have a short period to kill themselves.The kiss means “I loved you, you screwed me, so either kill yourself or well do it for you.” Its a small act of mercy for the victim because at one time they were close.