For some guy's it's not about everything it's not their "life" it's their "hobby". Sound's to me like your a hunting snob which is right by those purist's. If he is wearing pink who care's it's his life and not your land. As long as someone doesn't litter or poach or destruct land we should try and unite and be friendly. Maybe he is new and dont know better or maybe he don't care and just like's getting away from his wife or kid's. Either way let him revel in his glory and use him to your advantage as other's said.
And look at chuck adams, fred bear, ted nugent,our grandparents,etc. They all killed numerous deer and other game in t-shirt and jeans, dont make it more complicated then it is.
I have to agree with tc3383 on this one. I think you should have went and talked to the guy after he missed the deer. Told him who you are and that your cousin owns this ground, and thats your ground where the does went to. I would then talk to him and see if you could help him out and get his bow on target. Your supposed to be the bigger person.
I think alot of us here have lost hunting spots. I've lost two honey holes due to leaseing. It sucks your looseing your hunting spot. I get the feeling your mad at your cousin over it. Thats just not right. Its his land and he can do with it what he pleases. Start nocking on doors and find new locations to hunt. You might find a honey hole with some really nice deer to hunt! Roll with the punches and don't let it get you down. I don't let many things get to me because life is to short and I'm not going to waste my time getting ticked off and upset. It gets you no place. Thats what I think.
Exocet77 is also correct, who the hell cares what the person is wearing. I've killed deer wearing blue jeans. Biggest buck I ever shot at with a bow I was wearing brown duct coat (noisey!!), and blue jean overalls. He ducked my arrow at 25 yards. Deer could care less.