Suppose you inhabit a world where violent acts occur. You identify the aggression of one person against another as the common trait of those activities. An ethic called the Non-Aggression Principle (NAP) identifies that commonality as behavior which is desirable to oppose.
The identity of the ethic is limited to opposing aggressive behavior.
A necessary ethical cost of opposing aggression is a commitment to knowing if there is aggression, not how there is aggression.
A necessary ethical cost of opposing aggression is a commitment to whatever is without that aggression.
I contend that, by adopting the NAP, a person restricts themself from condescending to the manner in which others behave non-aggressively. To do so is to reject the peace they claim to hold the NAP's values in pursuit of.