In other countries like China, Japan, India, ... those edge cases are common enough to represent a significant portion of use cases and make X truly broken.
The article is maybe a bit provocative, but you know what, that's exactly what is needed to raise awareness of mainly US-centric developers who would completely ignore the technical issues until they face a clone in China whose only innovative feature is not breaking on Chinese text.
> *Strings work fine for the vast majority of use cases
In the CKJ space (a third of the population ?) strings are "broken" in the vast majority of use cases (really, things like what format you should accept for a telephone number). It get exponentially dirty as you try more complex manipulations, and I think these are interesting problems. It helps discussing them from time to time.