Americans are free to use the metric system
Such rubbish. Every country that had the metric system did so against the will of their citizens and at great costs. The US took a different approach and it works just fine, it let's individuals decide what to use.
When I cook, I often use the metric system, because its easier to weigh ingredients. I could also use ounces, both work just fine. But only for my own recipes, for everything else I use whatever system the recipe calls for. My scales and measuring cups have both systems so I'm free to decide. Almost everything I buy to eat has both metric and imperial units on the packaging.
When I build furniture or do diy projects, I almost always use the US imperial system because that is what most products are sold as and what many plans use. Many of my tools have both systems so I'm able to use whatever suits me.
When I drive, I use imperial because I have an old truck with an analog speedometer. But I could just as easily use metric since I use Google maps. Signs trends to be in imperial, but newer cars can easily be set to use either system. Converting between miles and kilometers is pretty darn easy. As is Celsius and Fahrenheit.
When I sail, I use nautical measurements like knots because the earth was 360 in it and they unit is based on that.
Americans are free to use whatever they want, no one has dictated to us what we have to use. Both imperial and metric are taught in school and measuring instruments for both systems are freely available.
For those unfamiliar, this is called freedom.
And since US schools teach both, it's obvious even a child can learn them. Not being able to use imperial or metric is a choice.
Or simple ignorance.