As Joseph Campbell once said;
Boys everywhere have a need for rituals, marking their passage to manhood. If society does not provide them, they will inevitably invent their own.
If we don't start acknowledging and making room for straight men having sex with other men this behavior will only continue in underground, dark and secretive places shaming the men who do it causing them to do it even more.
FEAR, RISK and DANGER
These are the crucial elements that cause these men to act out sexually with other men in public places. They are also what cause new lovers and couples who fight and make up to have hot, bonding and exciting sex. The fear, risk and danger of losing someone and being abandoned during the vulnerable time of attaching to new love or in conflict with your partner who you do not want to lose activates natural drugs within your body chemistry.
Natural chemicals such as dopamine, endorphins and adrenaline give sex its "high." Sexual behavior causes chemical changes in the brain, which promote a mood-altering and mind-altering experience.
Then there's a natural drug in our bodies called phenylethylamine or PEA for short. This drug is released when we fall in love each time. Like any drug, it's first release is its most potent which is why most people will say they "never got over their first love". They remember the chemical high that bonds attaches you to a partner.
PEA is an essential chemical for those who are addicted to inherently risky behaviors like gambling, shoplifting, bungee jumping, and sex. PEA's molecular structure parallels amphetamine, and is strongest when first released. This also explains why so many people with addictions say they're always seeking the feeling they had during their first high, and want to re-experience it over and over.
Great books to read about these chemicals to explain why men like Larry Craig would engage in public sex are