The fact that an investigation was eventually set in motion, once the affair had received widespread media coverage doesn't necessarily mean that what happened was a unique or indeed an uncommon event.   In this case the attempted cover-up of what appears to have been an atrocity did not succeed.

As for the question of people failing to call attention to the atrocities against non-combatants carried out by insurgents and the like - the point is, I haven't come across anyone who is suggesting that these are anything other than atrocities. That's not the case when it comes to the activities of the occupation, on the ground and from the air.