My husband's hairstyle is bad and I hate it.
That's not good! What do you hate about it?
It's a hairstyle that is a symbol of hazing and warfare
While it is their hair and they should be able to change it however they like to, it is okay to express your feelings about. As long as you understand that they don't have to do what you like.
You don't understand. I need to try and help him since he doesn't know any better.
It is okay to let your husband know you don't like the haircut and try to inform him, but at the same time we should be careful to assume we know what is best for others.  That being said he should be willing to work with you so you can both be happy,