Well in the case of GPL, what you are not allowed to do is to use GPL licensed code with yours and decide not to give recipients of the resulting code the same

Well in the case of GPL, what you are not allowed to do is to use GPL licensed code with yours and decide not to give recipients of the resulting code the same rights that you were given. I personally think that makes for a decent 'moral standing'. Basically GPL only a problem if you want to create proprietary software, which in turn is typically very much a 'being told what you can do with said software' type of situation, with no code and often incorporating DRM mechanisms to prevent copying.