Testicles are outside of the body in order to regulate temperature. When it is particularly hot, having legs together can be very uncomfortable for those with testicles.
If a person is taking up too much room on a subway, it is reasonable to ask them if they wouldn't mind moving up, and hopefully if they are a nice person they will oblige.
There is no "power-play" going on. We just want to sit down.
sage because this "man-spreading" bullshit detracts from what is actually an interesting and worth-while discourse on gender equality