The article says this about insertion sort:

This is the fastest sorting algorithm for small arrays, up to maybe 20, 30 elements. Even in software!

No no no. Insertion sort is fastest only when the items being sorted are in nearly sorted order. Its runtime will always be dependent on the number of items, n, being sorted. For a completely randomized array of items, it will run at O(n^2 ) regardless if n is small. Quicksort and Mergesort will do better in these situations.