Pretty sure St. Paul is talking about vanity.
Corinth was the playboy city of Greece at the time. In Paul's day ships would be hauled over land via the Corinth Isthmus, and while in transit sailors would go to pay their homage at the shrine to the goddess of love in Corinth, which was the fee paid to the temple prostitutes. It is no stretch of the imagination to suppose their were many homosexual or effeminate men there as well given Greek society at the time, which could be what Paul is implying as well.
