It's really crappy of you to advertise your game here, but not sell it here. Offering a demo here costs you nothing, but costs itch.io for hosting. If everyone put their demos here, but refused to sell here, then itch.io would disappear. You're taking advantage of itch.io and the indie game community without offering anything in return. It's super easy to upload games here, and the only reason not to do it is because you don't think we're worth the effort.