Unless one is a gay, how could a straight person get turned on by a same sex encounter?
You're assuming straight people are absolutely 100% straight. That's generally not reality.
One can't be a little gay, or a little straight. Sure there's bisexuals out there, but the priesthood is littered by pedos who choose that profession, or say, a scoutmaster because that gives them the perfect opportunity to get hold of little boys for their own perverted fetishes.
One most certainly can be a little gay or a little straight. Most people are not absolutely pure in their sexuality.