That's a pretty lame shot at Christians. He said that someone needs to be held accountable, someone made a mistake and that there was someone to blame. That's it. He should forgive but it doesn't say that he's holding resentment in his heart, it sounds more like anger and confusion because he's upset over losing his son.
Apparently you wouldn't get angry and want accountability for peoples' actions if your child was killed. Oh but wait, it doesn't matter because there's no one looking at your life with a magnifying glass waiting for you to slip up so they can call you out on it, because you're not a Christian.
