all judgements of good and evil are fundamentally pointless because everything that has ever happened was inevitable).
That sort of reasoning would no doubt surprise many Calvanists.
I don't see the analogy between "again (Cortez)" and "again (the great game)" or Cortez and the treaty port system. What's remotely inconceivable about the great game? The conquest of India may be a different story but the great game doesn't yield crazy changes in the status quo.
In both cases (and in the case of almost every other country on earth with the possible exceptions of China, Afghanistan, Ethiopia, and Japan), the only consistent outcome to these purportedly accidental events is the subsequent emergence of European hegemony.
What makes the accomplishments of men like Cortez or Pizarro so astonishing is it's' impossible to explain by a level of brute resources being brought to bear. Pizarro took less than 200 men and came back with a massive chunk of South America overthrowing a massive empire. The conquistadores don't even have the "european miracle/great divergence" explanatory points open to them. "Why Cortez succeeded" is hard to answer. One frquently advanced point you've missed is the idea that the strangeness of Cortez and how he didn't fit into pre-existing conceptual framework made the system significantly more fragile than you'd expect. It's hardly a perfect response (in this form) but it's highlights a clear room for contingency where you frame non existing.
were not the deciding factor
Everyone grants the deciding factor (arrival of Cortez is the obvious changed variable) but "deciding factor" (marginal change that changed the result) is a different concept than apportioning explanatory power.
your Stefan Molyneux's railing against non-monogamous marriage until around early 2017
"alt-right figures ranting" isn't a good way to summarize vast literature and debates surrounding impacts of family structure including polygamy, cousin marriages, etc. these sorts of analyses don't even break neatly down along ideological lines