I didn't make a specific claim about what other countries did or did not do, just hypothesizing what I thought were the likely answers. Do you have evidence of your, very certain, claim? I imagine that if they did in fact ban fluoride (or is it fluorine?) there would be a law on the books explaining why and, if they are anything like the US, it should be publicly available.
For one case, the Netherlands had fluoridation of the drinking water from 1960 to 1973. According to wikipedia, opponents cited concerns of adverse effects, and the availability of other means of getting fluorine to the teeth.
I don't want to go into the good/bad discussion. Wiki states that too much fluorine may cause fluorosis of teeth and other things. I'll leave it to you to continue that discussion - but you might do it in a more cordial fashion.
As to the other means: my first dentist, 1970s, heavily plugged toothpaste with fluorine. He also administered once or twice a kind of fluorine-containing paste to my teeth at a 6-month checkup. Since years, virtually all toothpastes on sale here do contain fluorine. Also, dental care for children up to 18 has always been part of any health care insurance. So, methinks there are excellent means of getting enough fluorine to people's teeth.
Of course, these are social parameters that vary from country to country, so YMMV. In particular for the US, with its tens of millions of uninsured people I can imagine millions not seeing a dentist and those very same millions largely overlapping with those who do not give their children enough discipline to daily brush their teeth and/or do not know about the beneficial effects of fluoridated tooth paste.
BTW, there is no fundamental adverseness in the Netherlands against such additives. For instance, we've had for decades that all table salt sold had iodine added against thyroid problems, and bakers still use salt with added iodine.
