Yes, I think the others are on the right track.

In the USA, Canada (ex Quebec), Australia, New Zealand, and of course England, the vast majority of people traditionally have spoken English as their first and only language. English is the language most folks hear from the day they are born. It's the language they use for everything in their daily lives. Regional accents come from the language of the colonists, isolation, and time.

In Nigeria, the Philippines, India, and many other countries, English is used alongside other languages. Sure, some people do grow up in pure-English households, but I don't think this can be said of the majority. And even with them, when they step outside a lot of things happen in the local languages. Those local languages heavily flavor the accents of the English spoken there.

There's plenty of real racism in the world. I don't think this is an example of it.

The idea of "native speaker" is kind of a crock anyway. I know too many "native speakers" whose English sets my teeth on edge. And I know plenty of "non-native speakers" whose English is probably better than mine. When I hire, I look for "native-QUALITY" English, and this can come from anywhere.

Unfortunately many of my customers, and many owners and managers and students of English schools, aren't so enlightened.