The 'free-market' school of liberalism... is animated not by certainty about how to arrange the distribution of income (or about anything much, for that matter) but by regard for individual liberty and by scepticism. Liberty calls for markets because it requires, so far as possible, freedom from coercion: markets are places where people do things voluntarily. Scepticism calls for markets because a million experiments are safer than one big plan handed down by the Chief Engineer: markets weed out mistakes rather than entrenching them; their solutions to economic problems are always provisional, always adapting.
Liberty and scepticism come together in ruling out the idea that society should have any such goal as maximising GDP. The 'free-market' liberal is not so presumptuous. Some people want to maximise their incomes in the market; others want to balance that goal against different aims; still others have no interest whatever in maximising their income, and want to pursue their own idea of the good life in their own way.
I don't think i should quote so extensively, but I doubt they'll kick up much fuss.