Facebook is spending huge sums to root out hackers and trollers from its service. It is a fight the company says cannot be won. The strategy must be to contain and exterminate inappropriate content as quickly as possible when Facebook becomes aware of it. This hasn't happened quickly enough for regulators and Congress. Zuckerberg is promising to do better but he cautions that there is no silver bullet. He is right about that. Obvious racist comments and other objectionable material can be isolated quickly, but couched language and subterfuge cannot. The company is locked in a never-ending battle that it didn't envision when the software was developed. Chalk it up to naivete and a romantic notion that technologists have about the purity of the online world. They forgot that there is evil and people who do it. The human race flawed. Zuckerberg has learned that lesson the hard way.