I'd like to make clear, these aren't sanctions against Pakistan's government, or its military, but specific state enterprises. The US isn't stupid enough to Sanction Pakistan directly; the day the US reimposes sanctions against Pakistan directly, is the day that the US loses completely half of South Asia to China.
It has little affect, as these entities have little to no business interests or connections to or within the US.
The truth is, these sanctions only stop US companies from doing business with these 7 entities, and nothing more.
I imagine it has something to do with China assisting NESCOM in developing missile tech for Pakistan Army, in particular, its drone fleet.