Because they are completely unrelated?
what the user laminustacitus
said is correct. economics as a value-free science does not make policy recommendations. the moment in which an economist makes a recommendation he is no longer value-free but he has introduced ethics in his work. so, austrian economics tells us what really are the phenomena of interpersonal exchange, production and etc. but does not imply that we should do this or that. for example, on the one hand, Mises, who was a champion of AE, made propositions how should things be according to what he thought was a preferrable state of affairs - i.e. that of vast economic productivity, on the other hand, Rothard made propositions that were justified with the libertarian rational and absolutist ethics, which does not make him less of an “austrian”, since such a libertarian state of affairs promotes namely what austrian economics explains (economic activity that is freed from government intervention(coercion)).
in other words - one can be an austrian economist, but this does not imply that he is also a libertarian or classical liberal (or any other choice of political philoshophy).
Please provide proof of your statement. Where did Hayek ever say that welfare is a necessary or desirable thing? Hayek only proposed an alternative, more efficient form of welfare that wouldn’t be as costly or harmful as “normal” welfare. He explicitly stated that government welfare is not desirable. Saving taxpayers’ money is a good thing, IMO.