Engaging enemy infantry in a mosque, or other religious structures, is not unheard of. I've read accounts of snipers using the advantage of such towers, as they think they won't be engaged, and use it to at least try and pick off troops. However, such a defensive position gives the advantage to the enemy sniper, as it puts the friendly troops in the open if they wish to try and get close enough to clear the tower. That's when airstrikes might be called in to deal with the threat, as they have done so in real life. I see nothing wrong with the airstrike. It saved digital American soldier's lives. Digital civilian casualties are a sad fact of e-war.
Good kill, 2nd Lt Soto.