This is not a very convincing defense. Most foreign outlets Twitter and US media label state-affiliated are not directly controlled by the state. It's more like, hey, this institution gets a lot of its funding from, or has close ties to, the state, so just watch out for that which is 100% true here. NPR was literally created by an act of congress. You can't be honest and say in good faith it's not state affiliated.
Twitter directly states that the label refers to editorial control, and that even state funded outlets where the state does not exercise editorial control will not get the label (the BBC is explicitly given as an example.)
So, no, your explanation of the labeling logic is not accurate.