It's safe to say the 'sniper' is antichristian. The message of abomination is only emanated by somebody who disrespects God and is antichristian.
He exercises free will, and displays a resort to violence in his belief. This is a classic manifestation of evil.
Typically evil is used to destroy evil. It might be a do-gooder seeking fame or also arrogant, but also evil. It's also interesting how continued rebellion from God simply results in a spiralling downfall.
Many Palestinians and militant Muslims also fall into these pitfalls, but I'm not certain that Palestine is the root of the issue. I am sure that antichristian behavior and thought is the root of the problem.
We have a responsibility to defend ourselves, not to promote ourselves, or to do good, but to follow the will of God.