Comment by petsfed

There's also that, but I didn't go to the effort of investigating the rate of various strengths. I'll bet their data explorer shows that aspect of the phenomenon too.

I suspect that a major factor is that the great plains of North America are at a lower latitude than e.g. the Eurasian steppes, so 1) there are fewer people living there and 2) the confluence of meteorological circumstances needed to generate a lot of tornadoes (and therefore a larger population of very destructive tornadoes) just aren't present anywhere else in the world.

This whole line of reasoning "Americans must be bad at house construction, look at all the destruction wrought by hurricanes/tornadoes/etc" just feels disingenuous to me. Like observing "look at how much better the British are at building volcano/earthquake proof buildings, you never hear about people losing their houses to lave in the UK!".