It's a very natural human reaction to push back against the idea that someone else might profit from your work--whether or not you have any real opportunity to profit yourself. That was really one of the geniuses of open source licensing (including the GPL) as it developed. By contrast, in the PC world for example, there were a lot of licenses along the lines of "free for educational use only" or "you can't use this…
I recently ran into a modified MIT license with a no-military clause. My company would not use the otherwise very nice package because, unfortunately, it includes an "indirectly" in the language. We don't have anything to do with the military, but our clients are large pharmaceutical companies, so they probably have military contracts.
If your job is managing business risk, it's just not worth it.