As it should be biased.
The first example is what you learn in school. The other is what you learn on street.
But this story is what is expected coming the promoters on industry of perpetual racism.
I am sure it is also biased against Italian American English dialects, against Spanish American English dialects, Polish American English dialects, Germanic American English dialects, Indonesian American English dialects etc...
I notice that the author had no care about that, which tells you all about the authors and those that do propaganda to this.
Of course this don't tell you the whole story about any persons on said characteristics. It is a partial information.