Those developers generally make a big distinction between "work I do for free because it's fun or intrinsically rewarding" (like helping a charity) and "work I

Those developers generally make a big distinction between "work I do for free because it's fun or intrinsically rewarding" (like helping a charity) and "work I do to make a living." They will try to get maximum pay for the latter, partly to enable the former. So I think a better statement would be "if you don't ask for SUFFICIENT money for what you do SOLELY FOR PAY, then you're saying your work isn't worth much."