Justify all you want. However you justify it, it all comes down to the same thing. People are trying to help their children. They want to give their child an advantage that will help them in some way.
it is all the same, kindergarden holdback, 9th grade reclass, PG year at prep and non medical redshirt in college.
It is all done to help the kid gain an advantage.
I live in the city and psycho parents here holdback too but for academic advantages. If you have a kid born after June the pvt schools won't even accept them and force you to hold back.