Well, I never said you should just let yourself be stomped on. I can't speak for other nations, but in the US you do have the right to defend yourself. But, in the US, if you throw the first strike or make the first move to turn the situation physical, that then creates a situation where your actions may come under scrutiny.
If throwing the first shot is your fundamental strategy, then you may find yourself in a tough legal/criminal situation. It can be an effective strategy in a fight, but it can also land you in trouble, including behind bars.
Beware, and make sure you can justify your actions. In these discussions it is my impression that some people do not always do that.