I think it's because I'm a microbiologist. The smell a man has is directly due to bacterial colonization and not any intrinsic smell to the man although a particular man will smell a particular way due to the specific bacteria colonizing. I can walk through a lab and smell the same thing much more intensely so it doesn't turn me on.

Plus I was mostly playing with the guys. I only know of a few guys who shave their pits...mostly swimmers but also another microbiologist who agrees with me that it's kind of gross. I think it's hard to find my own hair disgusting and then embrace it on a man.