The reasoning is likely that in their mind, the two ninjas exist as a pair; they came out at the same time, priced about the same, have an entire event about just the two of them (fateful choice). Thus they're probably thinking that both should get equal representation. But Jonin Minato has been the one in missions for the last 3 months (I think, might be longer than that), and so they probably figured that Masked Man should get a turn, without really taking into consideration what the players would be looking forward to seeing.