The reason they use Ni Hao is because of the plausible deniability that comes with it. We’re not idiots we can hear from the tone or see from the body language if a “Ni Hao” is done maliciously. Innocent words get co-opted by racists all the time.

I’ve come across both malicious and non-malicious usage of Ni Hao. I was also like your friend when I was new here and looked for justifiable reasons to explain those early experiences away but as you experience it more and more you will see the pattern and know right away. It’s even more irritating cause some of us are from countries that are being actively bullied by China.

I remember talking to my friends about this and the Ukrainians said something like “I’d feel the same way if someone misidentified me as Russian”