It could only ever lead in a direction that refutes Leftist narratives. They pigeonhole this into the same box as IQ and race science, i.e. only malicious people raise such questions.

It's the same thing as how countries that were decolonised last (South Africa, Hong Kong) are vastly superior to those decolonised first (Haiti, Liberia) or untouched (Ethiopia, Thailand). Nobody can seriously argue that colonialism was destructive in lieu of this observation simply because the exact opposite should be true; that is, that countries colonized for lesser time periods should be less dysfunctional, and countries colonized for greater time periods should be more dysfunctional. But that isn't just plain wrong, it's the exact opposite of reality.

The Leftist psychological reaction to this reality is simply to deny it, reach into a bag of canned responses to pull out the usual excuse and then repress and ostracize whoever raised the question. Try raising this topic in a university if you have any doubts as to how it would play out.