There are so many male actors in Hollywood who have had or do have sex with other men and yet they don't label themselves as gay or bi. For many, they would likely consider themselves to be "sexually fluid", going with whatever sex is available, male or female, when they're horned up enough. There's also the inherent narcissism in many actor where they crave attention and get off on the adulation, not to mention showing off, either on screen, in public or in the bedroom.