The Fallacy of Political Reductionism is actually a special instance of a more widely recognized fallacy, known to logicians as affirming the consequent. For the benefit of those unfamiliar with this latter fallacy, a brief explanation is provided here.
A statement in "If ... then ..." form can be transformed into an inverse, a converse, and a contrapositive, as shown below.
Logically, the original statement is equivalent to its contrapositive: that is, if either one is true, then so is the other; if either is false, then so is the other.