I wince every time I see a photo like this. Several years ago as a volunteer firefighter I was in a house fire and was hit with a hose stream that threw me into a wall. The stream that hit me came from a 1.75" hand line on an adjustable nozzle. The stream the above protester was hit with was likely a smooth bore nozzle, which means water flows unrestricted under high pressure. Getting hit with a stream of water like that would be incredibly painful.