I don't think you seriously believe the NSA is trying to trawl for copyright violations. Arguments require more than just conflating some random facts and going 'there, see'.
They definitely are. Snowden literally proved this. They are collecting data at a MASSIVE SCALE. They are doing this as one of the commenters noted above; To find TS leaks and to find the next 9/11.
But they are logging that information in some database somewhere. So it's not a question if they care/ will enforce it now, but rather will they care or enforce it for the rest of eternity.
What people don't seem to understand about privacy is that once you give it away, it is gone forever. In some dystopian future where every American is assigned a social score, you pirating things in the early '00's may harm your ability to get a house loan.