Unable to find the article quickly, but, I read a compelling perspective recently: DoD vendors seeking to restrict use of 3d printed replacement parts that they would normally supply. There was some speculative tie-in with the recent wave of consumer level regulation.

If you put the DRM in the printer I can hard wire the stepper motors to some H-bridges and an Arduino and run the unsigned gcode.

I have no intention to print weapons, but just saying that this law does nothing.