"...but there are some military situations where it is essential to use weapons which are as selective as possible."

Nice sentiment, but not very realistic. Wars are never going to be as clean as we would like them to be, the smartest weapons go astray. From the the description I've seen of the slum these guys are holed up in, even house to house fighting, the most surgical option available, would cause severe civilian casualties if there are civilians are still there. They've had days of ceasefire to leave. Civilians have been fleeing from combat zones since the beginning of time. That's always their best hope.

Remember these are not Iraqi freedom fighters. Their leaders is wanted for murdering an Islamic cleric he disagreed with. Their own people have essentially disowned them and are trying to talk them out of the situation. Even with this combat, US Marines are still holding back. This could have been settled in a couple of days if they weren't looking for a more peaceful solution. al-Sadr could have ended this anytime he wanted to if it was his people he was concerned with and not his political power or his own hide.