Osama Bin Laden was not a good Muslim. He killed other Muslims and he killed innocent people, both prohibited in the Koran. It's that simple. Christians that kill innocent people are not real Christians, the same is true for Buddhists (yes, there are bad Buddhists) and Jews, Hindus, etc. It's a messy world and people get hurt when other people struggle for justice. But indiscriminately targeting innocent people as a means to an end is wrong and will never lead to a good end, whether it is terrorism or state sponsored terrorism, it is deeply wrong.