Morality is the purview of philosophers and the religious. Even those who try to loosely define morality as harm to individuals and society, you could argue that copying Matlab is immoral because it affects the livelihoods of those working for The Mathworks. Your argument that The Mathworks is not losing anything by Matlab being copied is pure conjecture on your part, as you don't have access to their marketing, sales, revenues, and other financials.
I realize that this discussion is simply re-hashing the whole free vs. non-free software argument that has been conducted on message boards across the interwebs for decades and the conclusion is always the same. You fall into a variety of camps that lie somewhere between Richard Stallman-esque "militant all software should be free" and others who use and contribute to free software but understand the position of those who sell software.