I totally feel for you (and everyone else) when it comes to dealing with rude people. I tend to cut non photographers a little more slack since they probably just dont understand or may not notice. But when a photographer is rude to another photographer it really burns my butt.
I was attending a reinactment of the battle of Monmouth in NJ. A rank of soldiers were getting to fire a volley. I had taken care to position myself behind all the people who were there before me. Most were not taking photos but were just sitting on the ground and on lawn chairs watching. I was standing behind them with my camera and attached Bigma on a monopod. I saw the officer just about to give the order to fire. I focused and just as I was taking the shot, Mr Canon White lens jumped in front of me so I got a nice shot of his back.
I probably should have let it go but I didnt. He moved to another spot and sat down in front of some family who was there before him. I walked over and stuck my monopod right in front of his lens. we had a few words... then he moved on.