From a mathematical perspective, this is actually not that surprising. Think of the act of clicking the first link in the Wikipedia article as a function that takes in the page you're on and outputs another page. If you call this function on itself over and over again (ie use the output of one step as in the input of the next step), you will eventually enter a loop. The proof of this is simple: there are only a finit…
Another way of thinking about it: There are N nodes that loop back to themselves. When starting at a given node, what are the odds that you'll never hit one of these N nodes? Additionally, we know that many of the N nodes are very general ones, like "truth", under which many topics roll up.