If conservatives don't believe a persons merit is determined by their income?

Then why do they profess that a progressive income tax 'punishes' hard 'work'? Discourages people from 'working harder'? Oh, and punishes the winners! Clearly this opinions are of a mind that ones merit is determines by ones income; as ones income and ones income alone determines whether or not you work hard or even work at all. So why deny the charge that conservatives gauge worth in monetary terms?