I’m guessing your understanding of the U.S. military stems from an overconsumption of hollywood movies.
My husband attended a military academy high school during the Viet Nam war. One of his teachers told of his captain being shot in the @$$. “Take that hill!” “No.”
All volunteer armies don't shoot each other. Seriously. I know this is a widely held cliche, and there ARE indeed psychopaths who kill but those are extreme anomalies. Even though most Soldiers and Marines dislike homosexuality there will be no "friendly fire". It's ludicrous and disparaging of the honorable to suggest so. Friendly fire accidents are generally due to area attacks such as mortar fire, bombs and the like.