Amazon makes it pretty clear they sell used products and it's hard to imagine people not realizing that they offer used products unless they are new to the site and have never searched for any number of out of print books or old video games.
They aren't banning all used products anyway they are only banning used Nintendo products which is a bit of problem when Nintendo stops making "new" copies of old games and consoles. If I want an original gameboy or a copy of Super Metroid I should be able to buy them on Amazon from every available seller and if I'm a small used game shop i should be able to sell my products on the largest market place in the country without begging Nintendo for their permission.
They aren't banning all used products anyway they are only banning used Nintendo products which is a bit of problem when Nintendo stops making "new" copies of old games and consoles. If I want an original gameboy or a copy of Super Metroid I should be able to buy them on Amazon from every available seller and if I'm a small used game shop i should be able to sell my products on the largest market place in the country without begging Nintendo for their permission.