Good for you for standing your ground and normalizing breastfeeding, and that's great that your husband was so supportive.
It sounds like the guys' comments were sort of silly and immature, but not truly hostile -- I can kind of see how a bunch of 20-something military boys with beers in their hand would say stupid stuff at the sight of breastfeeding. But hopefully the fact that their friends are breastfeeding unapologetically, and acting like it's the most normal thing in the world, will stick in their minds. And maybe when their wives have babies that's something they'll remember.
I can recall, before I had a baby, not knowing exactly how to react when someone nursed their baby in front of me -- and I was 1,000 percent supportive of everything breastfeeding. I remember not knowing exactly what to do with my eyes, being curious and wanting to look but thinking it might be rude. One of my goods friends came over a few days after the baby was born, and again, she was totally pro-breastfeeding, but I remember she was making this hugely concerted effort to look directly. into. my. eyes. and. not. at. my. boobs. It was hilarious and once I laughed and told her it wasn't a big deal, she relaxed and everything was fine. She just hadn't seen it before.
I think that's just a product of breastfeeding not being normalized enough in this country -- it's just not something that many people frequently see. Of course, now a bunch of my friends have babies and I'm so used to seeing nursing that I barely even notice it.