I live in Britain, which compared to the USA has severely restricted gun laws. However, i can appreciate your situation: my father owned a gun license, and he was also a hunter.
He used to hunt rabbits, deer etc. Anything that moved in the wild really. He'd take them home and gut them at our house. As i was his son he'd try and encourage me to help him out. It was utterly revolting yet he seemed to find it satisfying. I can associate with your revulsion at these men who take enjoyment from killing animals.
He took me out a few times to test me with pellet rifles, hoping i would one day pick up his hobby of hunting. I detested it from the beginning, but luckily my mum also disliked hunting. He was disappointed at my lack of interest and often mocked me as being weak. He was forced to give up his shotguns when one day he almost shot his own father by accident in the house when cleaning one of them. He forgot to unload the thing!
My advice to you would be to stand up for your beliefs. You don't need excuses: just don't compromise your ethics, that shooting innocent animals is wrong. Like you, i cannot understand men why certain characters of men gain pleasure from shooting an animal that cannot fight back. You cannot change these people, but what you do have is the right and ability to control your own life and what you do with it. Do you really care if these people regard you as odd because you don't agree with hunting? I personally wouldn't care very much what these people think. Don't allow anyone to compromise your personal ethics, compromise your personal happiness!
If they are entitled to their opinions, so are you. I felt very pressuried by my own father into accepting hunting, into participating. I refused and although at times i felt small from his mocking of me, now i look back i am proud of my standing up for my own personal ethics in the face of peer pressure.