I am not straight or bisexual. Whenever I get my balls and penis waxed, whether by a man or woman, I always get an erection. I also get an erection when disrobed at the doctor's office alone in the room and waiting for the nurse or doctor to come in to examine me, not knowing if the nurse or doctor will be man or woman. I don't want to have sex with these people, yet I get an erection.
I'll get an erection when the wind blows and I'm naked, alone, by the pool. Same when I'm close to a water jet in a hot tub. The wind or water jet is neither male nor female, yet it gets me hard!
The statement above is akin to saying a gay escort can't get an erection with a client that they are not attracted to. Bologna. Besides, straight men get erections all the time when having sex with their own man hand during masturbation.