The Peachums’ feelings about their daughter are hypocritical and contradictory. On the one hand, they are clearly right to worry about Macheath’s morals. On the other, their own morals are no better. (Of course,
they are also a couple of married gamblers and thieves—although they later clarify that their marriage is just common-law and not legally valid.) Indeed, they appear to care less about Polly’s wellbeing than about her pocketbook. So while their critique of marriage is legitimate—in the 18th century, women literally
did become their husbands’ property—their motivations for making this critique are questionable at best.