He was right, he did own the book, but only the paper and the binding, not the ideas expressed by the written words. It is these words by which a writer makes his trade. When the words of this writer are stolen everyone in the Ummah loses. The writer obviously looses. If the writer is a woman she has probably taken the time to write away from her family, house, husband and children, if there is no monetary reward she will not continue to bother.
Monetary reward is sometimes necessary to placate a disgruntled husband.
In any event Muslim writers, or any writer, who have had their work stolen become disheartened and cease writing. The company that chooses to publish a work, sets aside a certain amount of money to print, bind, sell, advertise and distribute the book. The publisher hopes and prays that he can make back all that money and little more to support new projects. When a book is stolen the publisher must mark all this as a loss. He is more reluctant to take on new projects and indeed has less money to do so.