I didn't say you hit the truck first. I was pointing out that in most states, you are responsible for being 'in control of your vehicle at all times' and they typically ticket you if you hit the rear end of a vehicle. I have seen several people get ticketed for the 3 car chain-reaction due to 'following too close' because, per the letter of the law, you were stopped too close to another vehicle.
Not saying that I agree at all, because I think the person that hit you initially should be responsible for all vehicles- but that's typically the way the law is interpreted. This is why everyone that rides with me gets so irritated by the fact that I stop 1.5-2 car lengths behind the car in front of me.