Then why have they mainly been used in developing countries?
[1] https://worldpopulationreview.com/country-rankings/bathing-h...
America is very backwards and hilariously underdeveloped in some areas especially in day to day life. The fact that the parent comment calls toilet paper "sandpaper" is another example.
That seems quite hyperbolic. It's not as though you can't buy or find a bidet in the US...
The other 2 countries I know of where bidets are widely common are the ultra-modern Korea and Japan.
[citation needed]