Wow... had not heard that one before. And yeah, I cannot see it as anything but a slashing mutilating weapon, not useful for anything approaching self defense. And then of course, it brings to mind the Lorena Bobbit thing....
When I was young and enjoyed being in a violent world the straight razor was popular for scarring guys in fights, men who could fight but wanted to mess with the guy they were taking down.
Cross dressers/trans liked it for the dramatics, the scarring, the intimidation, and it can end fights in a dramatic manner by whacking and slashing the head which causes lots of bleeding on the eyes and face.