I recently processed (okay I think I was more watching with him) a Muscovy. I had never had duck meat before. Not too bad. He was roasted with bacon and apples.
I am sorry you were horrified by the sight. Some people don't get over it. Some people see it as a show. In the middle, people that behead will hold the bird still, or place the body in a feedbag (as Sally mentioned above) which keeps you from seeing and preventing the bruising of the meat.
Please don't feel bad about it. It's like a rocking chair rocking after you stand up.