Agree with the others-- this is a matter of an individual who believes that chronological age is synonymous with particular developmental milestones, and that is patently and demonstrably false.
When children are ready for abstract thinking and symbolic representations, they are ready for algebra. Different students are ready at different ages. I venture to say that some of them aren't ready yet when school believe that all children SHOULD be taught those concepts, either.
What's weird is that a lot of people like this believe that there is a tail on THAT end of the distribution, from a developmental standpoint, but at the same time, do not believe that there might be a tail at the other end.
