> In the article n was set to 5. All of those arrays (except maybe 1) have exactly 5 elements. There is no variance

No, the code was:

    # If there are < 5 items, just return the median
    if len(l) < 5:
        return nlogn_median(l)

> and even if there was, it would be tiny, there is no point in talking about limits of 5-element sequences

So your point is: not all constants are created equal. Which circles all the way back to my original point that this argument is pretty funny :)