Tell me, if you are being attacked by a guy much bigger than you. You have gun, that can shoot him down, wouldn't you fire? Then why is it different when someone comes to attack your soldiers? Your soldiers' life must be protected. Chahay koi bhi hai, kill the bloody attacker down.
Its not like they didn't have the capability to shoot down the choppers. The ISPR report pointed out that they didn't have the capability for aerial defence. After the Osama raid, this is criminal negligence on the part of the leadership. After being reported that the checkpost has come under attack and not scrambling the PAF in defence - thats plain criminal.