Perhaps there is little correlation between those who excel at coding at a young age and those who go on to be good programmers when they get older. I just find it interesting that at this young age I see a correlation between coding skills and language skills more than math (really just arithmetic) skills.
Another observation was that we did the Hour of Code activity in December last year with Year 2 to Year 6 students (equivalent to Grade 1 to Grade 5 in the US). And in each group there was one or two student who really stood out. And every one of them was a girl. Small sample size of only about 100 students so maybe I shouldn't be wondering what is going on here.
As the other comment above mentioned, I think this has to do with education of the teachers. Very few teachers know what math is either.