Why is the first claim more 'fantastic' than the second? Why are nurture-arguments so often viewed as perfectly innocuous and impartial, while nature-arguments

Why is the first claim more 'fantastic' than the second? Why are nurture-arguments so often viewed as perfectly innocuous and impartial, while nature-arguments are viewed as so controversial? Throwing around unsubstantiated claims about how "society molded them into who they are" seems like a very fantastic claim to me. And I see a lot of that kind of argument going around.