I believe it's due to a common false dichotomy. There are plenty of observations around where women respect a man that treats her below par, and it's convenient to jump to the conclusion that it means treating Her well leads to a loss of respect. After all, our minds are being more and more shaped to think in binary opposites, and it takes self-awareness and energy to even spot that. We (at least I think so) have it easier seeing it because we are making conscious thoughts about those sorts of things. (Also, the psyop cuts from the other side too - "if a man treats you well, you are too good for him" kind of thinking.)