Your entire thing seems to be that you can't easily convert between units. Speaking as an American who has lived in metric countries for the last decade, that's bullshit. Nobody ever needs to know how much a liter of water weighs. Nobody ever converts dekameters to hectometers. You just stick with one unit, the one that's suitable for whatever you're measuring.
"When you say "pound" do you mean force or mass?"
Fucking hell, when is the last time anyone needed to actually use this? "In the lab the other day" yeah right we're not talking about edge cases.
Moreover, if you're a drinking man like me, the metric system is a ripoff. A bottle is 12 fluid ounces and that's all there is to it. 355ml. With the metric system, at best you get 350ml, and it's really easy to slide down to 325ml, 275ml, and so on.
If they showed any tolerance, it wouldn't be a zero-tolerance policy.
You asswipes demanded this, now you got it. Deal.