Why do i want to have sex with smelly people?

Ok so u see a hot guy walking down the street in like worker gear or tradesman clothing and when they walk past you, they have a little (or alot) of the BO smell. I like this on good looking guys and want to have sex with them so bad. RIGHT THERE!! but i find it utterly foul and disgusting on myself, fat people, unnatractive people, homeless people and females. Oh and im a gay male. Is this normal?