Weird to have to explain this here, but: China is a country with a border. Chinese is the nationality of this border. There are over a billion people there, the only people who think China is full of Han alone are ignorant Westerners because we get this extremely reductive view of Chinese culture. You should go visit and you'll see for yourself :)

Said people still live in China though, what else would you call these provinces. China != "Han", although majority of China is Han. It's interesting how our language sort of ties, ethnicity and nationality together when the two are very separate things.

Maybe this occurred because rulers wanted people to identify with their nation (and pay tax and die defending it) instead of their tribe. Or maybe it is just because nations used to all be ethnically homogeneous. It certainly doesnt serve us well these days though! Very confusing

it's worth pointing out the hong kong/china divide, where both are predominantly han but it seems that national identities have diverged.

China has always been ethnically diverse, and twice has had dynasties not led by ethnic Han. It's okay to call them Chinese.