When someone decides to write some very useful software to sell it and someone else "copies pixel per pixel" the software is simply stealing the original author

When someone decides to write some very useful software to sell it and someone else "copies pixel per pixel" the software is simply stealing the original author work. If you want to write your software and release it with an open source license you are perfectly able to do it. If you are simply doing an exact copy "pixel per pixel" of someone else work and releasing it as an open source you are stealing his intellectual property given that the original license is NOT open source. I really love open source, but people that think in this way seriously risk to undermine my trust on the whole OSS model.