Define “theft” in an intellectual property context. When something can be copied without destroying the value of the original, what does it mean to “take it”? What harm is caused? What does “belonging” even mean, in a context where no author can *ever* produce a truly original work, IP laws notwithstanding? I think you need to make a convincing case that the digitizations caused harm to the authors or detracted from their sales somehow, before you can call this theft.