Abu Musab al-Zarqawi personally beheaded and cut the throats of people who had done him no harm. He blew up mosques and market-places, shredding the flesh of innocent men, women, and children in their thousands. His war aim for Iraq was to spark a generalized sectarian slaughter. He was an enemy and a roadblock to whatever freedom the Iraqi people might eventually win for themselves. He claimed to serve his religion, but his god was Death, and his faith was in Terror.
The subtraction of such a monster from the world of the living makes one feel happier to be a member of the human race.