I think that may have to do with the fact that your Culture/Country hasn't really changed all that much... so respect and honour are just a part of who you are where you're from.
The US is an amalgamation of everybody from everywhere. So there's no real "core" culture. It's bits and bobs of races, creeds, beliefs, traditions, and individual cultures. What is acceptable to one may not be to another and vice versa. That can create conflict and ultimately disrespect and over the years it just kinda keeps growing and evolving and that's where assholes come from.
I was raised, and still believe to this day, "You get what you give." I don't have anything against anybody and as long as there's a mutual respect- we'll get along just fine.