Not too surprising. English teachers tend to disagree about a lot of things, like the serial comma.
The English language is pretty much shaped by how people use words, and when someone says 'peoples', they're either using incorrect English or are pointedly referring the different groups. Not like you have to accept it as good English, but eh, the important thing is that you understand what they're saying.
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"Duel audio? You mean like rap battles?" - termina_rzident
KrahenProphet and Kana are on opposite ends of the Awesome Spectrum.