CHOPPING 101

I have never proclaimed to be a "cooker" nor do i pretend that i can cook, but surely i have chopped many an onion in my lifetime to know a thing or two about chopping.
Well.......I don't.
Here is an invaluable article regarding 10 techniques every cook should know (like "spatchcocking"??), and here is the real/right/efficient way to chop an onion.
Can someone tell me why this was never taught in 7th grade in Mrs. Yap's home ec class? It makes so much sense not to cut all the way through the onion root so when cutting cross-wise the slivers don't slide around and there is more to grip onto.
Now I know and you know, maybe you already knew and, knowing is half the battle!