The wiki page specifically says that it's highly criticized:
Several political scientists, psychologists, and sociologists have criticized the horseshoe theory. [...] political scientists do not appear to support this notion, and instances of peer-reviewed research on the subject are scarce. Existing studies and comprehensive reviews often find only limited support and only under certain conditions; they generally contradict the theory's central premises.
Just because it has a wiki page does not mean it's a valid theory.
We need a Trek-style Retroencabulator video
https://youtu.be/RXJKdh1KZ0w