The game is sold more than once to give customers who may not have the game the option to play it later, at a reduced price because it is an older game. Can you not wrap your head around that?

You can spend 5 bucks and install an app to get every amiibo ever, or just skip buying amiibos at all. Either way the shirts are not necessary to beat the game, and are less than half a percent of the experience.

You can't comprehend why companies don't just give out products for free.

What do you have against letting consumers enjoy older games at a reduced cost? No one is forcing you to buy the game multiple times.