Just like when you buy a book you’re allowed to photocopy it and sell the copies?
Creating a copy is violation of copyright. Owning a book, reading it, then reselling the copy you own is not.
'Buying' digital goods nowadays means the vendor can take the goods away from you at any time, for any reason, with zero compensation, and absolutely no possible way to recover said goods.
Correction: creating a copy that doesn't follow fair use requirements, is a violation of copyright.