Sure, and other developers want to get paid for their contributions, so they use copyrights. Pirating those pieces of software is only not theft in the narrow sense of not literally taking an object that can only belong to one person. But it's clearly breaking some sort of agreement of exchange that the creator tried to build into this process, which is some kind of immoral.
That's not to say that every copyright is good or makes sense, but blanket statements like "piracy is not theft" are either so narrowly scoped to be useless ("it's not theft, it's some other unethical action") or ... wrong?
