Giving as good as you get

A couple times I've heard the phrase "give as good as you get." It refers to the idea that if someone insults you, you insult them back equally. Is this a staple of American culture? If so, I condemn it.

Yes, I agree, if you are 100% sure someone is a complete jerk and is doing it on purpose, then hit back hard, verbally, physically, whatever. But what happened to human decency and cutting people slack? Maybe it's because I'm Asian and Asian people have doormat culture? The idea to "give as good as you get" without any kind of reflection is incredibly rude. What happened to those Christian ideals about "turning the other cheek" and not retaliating?

This is something to keep in mind when playing competitive sports. I like what judoka Ronda Rousey said in an NBC Olympic interview titled "International competition":

People on the mat are a completely different personality from when they are off the mat. When someone is roughing me up and trying to bust my lip or whatever or doing cheap stuff on me on the mat... I won't hold it against them because they could be the coolest person to go out with on a Friday.