If you believe everything is socially constructed, then you have already been indoctrinated and are beyond influence by evidence.
Social construction is one influence among many – and very rarely the most important.
Evolution – the differential survival of variants in different contexts, seems to be at the root of most of what we are (in both genetic and behavioural terms).
Many post modernists take an overly simplistic approximation to the complexity that is evidently present, then proceed to use that to justify whatever they are inclined towards (mostly such inclinations are the result of factors they haven’t begun to consider).
So I align with post modernists to the degree that I accept that all knowledge of physical reality (as distinct from logic or mathematics) is most likely some sort of simplistic and probabilistic approximation to whatever reality is.
But I diverge beyond that, because it seems abundantly clear that there are useful mechanisms for determining the sorts of probabilities involved most of the time, and often the heuristics in use are extremely reliable indeed.
I also acknowledge what seems to be the reality, that all of our experience is of a subconsciously created model of reality (never reality itself), and that mathematics and logic are the best modelling tools we have in building our best approximations to whatever we and reality are.