Permissively licensed software is intentionally designed to be used by anybody for any reason with essentially no restrictions beyond attribution. Advocates of permissive licenses explicitly reject the argument that commercial users ought to have any kind of obligation to the authors. "Thief" seems like a category error here.

For people who want to make money down the line, what is so hard about selling commercial licenses? Or better yet using GPL so that your software is still open source but the big commercial users will still want to pay you for a separate license?