I was primarily making a joke. But it is indeed a big pet peeve of mine.
I do find it annoying that one country in the world likes to use it's own unit. And that of course they are not as nice to use as the units optimized for science. It is annoying for international communication.
But my real issue is that Americans seemingly lie to themselves by pretending everything can be rounded off to the nearest approximation of US customary units without consequences. And so anything you buy in the USA; unless maybe when manufactured with US customary units; is not the advertised size. Worse yet, this habit of rounding off is also applied to US customary units in many case. Because nothing is ever the advertised dimensions, or the tolerances are just laughably large. Nothing ever fits. That is what I am fighting.
Ask for a 48" long piece of lumber in the USA, you get something +- 1/4" at best (+- 6.35mm). Go to my home country asking for 1.2m will get you something +- 0.5mm. It's cultural.