This seems like a piece of propaganda a politician makes up before declaring war, or a paragraph from a children's cartoon about good vs. evil. If only the real world could be cleanly divided into such clear categories!
The moment we declare someone "evil", we tend to forget that the "evil" person is a human being with essentially the same DNA, same brain, and same emotions. We neglect to consider the possibility that we could be that evil person, if we had his upbringing and experiences. We also neglect to critically examine the factors behind that person's evil views in an effort to prevent those factors from surfacing in others.
Let's critically examine Osama. He obviously has no qualms about violence against civilians, but his goal is not to kill as many civilians as possible; it's to diminish the oppressive influence of the United States in the Middle East. We can argue forever about the ethics of killing civilians in a war with an oppressive regime, but in practice every country, including the United States, accepts that civilian casualties are inevitable in a conflict and believes that they're justifiable if they help reach the military goal.
Another point: Osama killed only 3000 civilians in the WTC attacks, and even that is many times greater than what he planned for. The 1948 civil war that started due to the United Nations forcibly partitioning Arab territory had 10,000+ casualties. The 1982 Lebanon invasion that Osama used to justify his terrorism had 30,000 Arab casualties, about 10,000 of which were civilians. Others have already mentioned the Iraq War, which caused hundreds of thousands of civilian deaths. These numbers alone dwarf the 3000 killed in 9/11. We haven't even begun considering Israel's human rights abuses in the West Bank or Gaza Strip.
I'm in no way supporting bin Laden, but his actions are at least understandable from the perspective of a delusional religious nut trying to end the (not entirely fictitious) American oppression of the Arab world.