Possibly because the major software companies made it work on phones. Thus users saw it working on many apps and complain when your app fails to do this. Googl

Possibly because the major software companies made it work on phones. Thus users saw it working on many apps and complain when your app fails to do this. Google, Apple, IBM and MS also did a lot of localisation so their code bases deal with encoding. It is FOSS Unix software that had the ASCII mindset, probably as C and C++ string types are ASCII and many programmers want to treat strings as arrays. The MacOS and Windows APIs do take UTF as their input not char * (agreed earlier versions did not put they have provided the UTF encodings for 25 years at least.