Because you put a ? mark at the end of the sentence.
I don't think the marines in Aliens were hardened. Seems like corporate military with tons of weapons, got paid good, never saw anything. They talk more about getting strange then seem like they are battle tested. Many of the Marine characters didn't do too well handling it, dang, the person in control only had 1 combat drop including the one they were one, but had 28 simulated. And, it being a movie you always have to have someone freak out more than normal. It's just Hudson freaked out better than any other war movie which makes it so quotable.