The excluded middle ( A Law or an Heuristic) .
On a more general level given any closed question: Is it A or B ? , the heuristic says it is one or the other disregarding the option : the question is wrong or stupid or irrelevant or incomplete.
The principle of excluded middle disregards intuitionist logic. And has been harmful in not providing direct (constructive) proofs which are often more clear - yet can be harder to find.
Intuitionism is is also rather natural : being against anti-communists does not means you are a communist.