Humans shifted to monogamy (patriarchy) for very clear and well-defined reasons that I've already stated in the OP - related to changes in food production, which also brought about a new dominance-based hierarchy and some other cultural and environmental reasons that I didn't go into in depth. If patriarchy had brought on a naturally more monogamous way of living, there would have been no need for the strict controls of women and the severe punishments that arose if they did not comply with those. It would have just all flowed naturally with no coercion or need to control women. But that wasn't actually the case -so we know it wasn't natural.

We've always had pair-bonding. The expectation of sexual monogamy is what was new. As I said in the subtitle, conflating those two is a mistake.

I'm not saying it should be one way or the other either - I'm simply commenting on an assertion that I've often heard - which is trying to give a scientific justification (one that doesn't actually exist) to a social more.