But that isn't what it means in the context of theft, and linguistically the distinction is clear unless you are being disingenuous. There is absolutely no linguistic foundation for equating theft and duplicating information.

Legally the distinction is also clear - transgression of copyright law is specifically given the term "copyright infringement" in law in English speaking countries and in international agreements. A person cannot be convicted of theft for copying information. The US supreme court, among others, ruled on exactly this:

https://en.m.wikipedia.org/wiki/Dowling_v._United_States_(19...

If its an unsound argument, why are copyright and theft different bodies of law?