Because a topless white man on a motorcycle is too mainstream.
This is one of my favourite pictures on the internet. It smashes so many stereotypes at one time that it’s hard not to love it. There is not much information available on the internet regarding the photograph, hence not credited. The only guess is that it was taken somewhere in Northern Africa, possibly in the late 40’s or early 50’s. Here is the original (or not) source of the photograph.