Let's forget about Liberia and Myanmar and just focus on major economies. People can argue about the definition of "major", but for the purposes of this discussion, let's define it as G20 members.
In how many G20 members does the average person make significant, regular use of non-metric measurements in their daily life? To the best of my knowledge, the answer is "only two" (US and UK), and for the US that usage is significantly more than the UK. So, there is a very real sense in which the US (and to a lesser extent the UK) are outliers on adoption of the metric system in everyday life. That's not "bullshit".
> >The US is an exception in having an education system which still teaches non-metric measurements.
> This is too vague to even determine if true.
I have lived my whole life in Australia. Here, non-metric measurements are not part of the government-mandated curriculum. That was true when I was a child and is true for my own children who are at school today. Schools and teachers are free to teach whatever they want (within reason), but if it isn't part of the official curriculum, there is no incentive for them to spend any significant time on it, so the vast majority won't. Most school children have heard of inches/miles/etc, but for most of them their understanding of it is limited to "outdated stuff we don't use any more but Americans still do"
Most countries worldwide are closer to Australia on this than to the US. I mean, how much time do schools in France or Germany or Japan spend on teaching how many ounces in a pound or how many yards in a mile? How many countries – other than the US – have learning details of how to use non-metric measurements in their standard school curriculum?