What? Raikov was Volgan's gay lover, they infer that several times throughout the game and Volgin practically say it later on near the end of MGS 3 when he fights Big Boss. The whole concept of Raikov to begin with was a riff on Raiden being effeminate and of questionable sexualty in MGS2.
It's not like this series doesn't turn its joke characters into important plot points. See: Johnny Sasaki.