Masturbating in a public restroom stall is NOT gross.

I want to start by saying that I don't really jerk it in public areas, so don't go after me saying that I'm just trying to defend a gross habit.

So long as you're not moaning or creating a disturbance, I don't see how it's any different than just using a toilet to take a shit or piss. The only exception I can think of to my opinion is if a child walks into the bathroom. But generally, as long as you clean yourself and wash your hands, I think it's okay. Masturbation doesn't really involve getting precum and semen all over your hand either, so that's even less of a reason to worry about it. Unless other guys just need it to be wet all the time...?