This thread was not about a "low-balling mentality" on this or any other forum. It was about how one responds when they place ad to sell a car, and someone offers them less than what they thought was fair.
It is a "no-brainer" to say that nothing is gained by insulting the low-baller, other than perhaps stroking a too-fragile ego. What's wrong with just saying, "no, that is not close to what I would accept," and making a counter-offer (or not). It wouldn't have taken any more effort to respond in a more appropriate fashion. That's what this thread was about.