Uh, because your definition is not complete? Could that be where the fault is? The U.S. does not target civilians. It does not attempt to strike terror and inflict harm upon civilians. It doesn't aim to kill children, women, old people on buses, kindergarteners in school, nor does it kidnap legitimate soldiers while they patrol sovereign borders. You might not see any difference between the U.S., Hamas, Hezbollah or any other terror group that Iran funds, supplies and trains but only indicates your position, not reality.
Saudi king to meet with Obama on Friday amid Gulf concerns over Iran deal (Reuters)
from the article: Iran's parliament approves labeling CIA, U.S. Army terrorist groups