Every other business that deals with the transfer of money (banks, for example) is expected to put strong measures in place to make sure that the money is traceable and that they're not helping criminals. Why shouldn't large companies like Target be held to a similar standard?
Moreover, the incentives here are very worrying. Yes this guy got scammed out of $3k, but Target also got $3k in revenue. Without some sort of penalty/punishment, Target is incentivized to do the bare minimum to minimize their PR exposure (which they can do by saying "we take this very seriously and have adopted some new policies" but not really acting on it) but to otherwise allow this to keep happening. As the prevalence of these gift card scams has skyrocketed, so have gift card sales for these large companies.