The law only says teachers must come from a native English-speaking country, the big 5: Canada, UK, USA, South Africa and Australia. Twenty yuan says this requirement isn’t from Chinese people, it’s for some school for children of racist diplomats. Beijing is just the worst.
I remember the sentiment started shifting around 2012? 2013? Whenever those brits made the news for assaulting a woman. I haven’t followed if there were more examples since then, but thats the general sentiment I get from extended family, though they may be biased because they lean to being 小粉红.