Terrorist are defined as those who kill innocent people for their aim. So was ANC in South Africa terrorist, they were described as terrorist by the western world (at least by the US) but its ok for Polish people to fight back and kill when Germany invaded Poland, which would result in innocent German civilian deaths too. So how do we define a terrorist. Is LTTE a terrorist organization, because what other choice did they have after 30 years of peaceful demonstration, is IRA a terrorist organization (dont know much about IRA), etc, where there are perhaps situations where the government of the day discriminates a section of the people, like apartheid south africa. Was it ok for the SA government to kill blacks but not the other way around.
I would define Taliban a terrorist organization but its just as bad as another country invading another for no reason. I believe US had enough reason to invade Afghanistan but not all invasions are justified and in that case, who is a terrorist.
I guess terrorism is defined by who has the biggest propaganda machine and its a pity we fall for most of the propaganda.