People decide to kill people all the time. People order others to kill people all the time. People advocate for others to order yet others to kill people all the time. Some violence is legitimate. Some violence is justified. Plenty of violence is neither. But to ignore the violence of the state as sanctified, while condemning all violence against it as madness results in an alarming ethical framework with abhorrent conclusions.
Also, I would argue that it has more to do with mental framing than “being crazy”. Police and military leadership hire selectively and craft training to ensure that people aren’t mentally ill and still willing to kill.