I must admit that this response is quite irrelevant to your view expressed above.
I remember previously you made a post in BK (click here), saying that you were an English teacher and recommending "Rxxxxxx Kxxx" to BK parents because you found it very useful in helping kids to drill their English skills.
Unfortunately, I note that many BK parents have claimed that "Rxxxxxx Kxxx" has a lot of grammatical errors. What do you think about the parents' feedback?