I disagree strongly with Michael Berg's views. However, I also cannot condemn a parent's mindset after losing a son to such horrifying brutality. I won't call him, "crazy" but I can understand how someone would become "crazy" in such a situation.
BTW, I do not know how someone could forgive the "unforgivable". Forgiveness or not by Michael Berg, Zarqawi and his murdering thugs WILL NOT be forgiven by God.