Whatever good he did in the past (when he released the video of the Reuters journalists being killed by a US helicopter gunship)
And if we are going to be absolutely fair, that journalist decided to embed with the opposition in the hope of getting some combat footage.
The footage in which it shows him being killed clearly shows the group that he was with being armed with AK47's & at least one RPG. The group then only gets strafed by the Apache about 30 seconds after one chap aims and looks to be firing around the corner of a building towards the US troops the Apache is flying top cover for.
So it's not as if the US Military deliberately went aiming at a journalist or did something utterly unjustifiable. He just happened to be 3 meters away from somebody shooting at US forces in a war zone when they shot back.