The first step in understanding any complex phenomenon, particularly those which at first may seem incomprehensible, is to classify it. Classifications need not be definitive, or even correct, but they help organize our thinking about a phenomenon and lead to asking the right questions. Later, the classification can be modified or even discarded, but a first step is essential. And of course, the most basic classification is the dichotomy.

For example, today, we classify living things by the chemistry in their DNA. This classification is a slight improvement over the one we used previously, to which it is related, a branching tree of anatomical structures. But when biology first began other classifications were applied, not all of which were useful: was the creature terrestrial or aquatic? Was it wild or domesticated? Was it useful to man or not? Was it mentioned in the Bible or not? Edible or not. We still think of plants this way: plants vs weeds. Some of these classifications might even have had some utility (is it dangerous or not?). Today we feel the most useful classification is one that is related to the organism's evolutionary history and relationships to other life forms.

The dichotomy, like the list mentioned in your linked article, is the simplest and most basic means of organizing reality. It even has a mathematical formalization (see G. Spencer Brown, "The Laws of Form")
where the archetypal operation of understanding is the initial division of the whole into two parts. The "tyranny of two" is everywhere in nature, positive and negative charges, in and out, up and down, one and zero, left and right...I could go on.

Of course, the real world is often more complex than that, and the artificial worlds of philosophy, economics and politics we construct in our minds are more complex still. They are fundamentally multidimensional, but in their simplest form can be ultimately reduced to the two sides of some metaphorical coin. Unfortunately, some small minds can never get past this initial insight and move on to a higher level of understanding. For them, everything is always good/bad, black/white, yes/no, right/wrong, us/them. And anyone who even tries to teach them otherwise is always accused of being bad, black, no, wrong and them.