Whilst ESR is very keen on very rationalist views of the process, such short sightedness can cause you to umm, literally, loose your head in the next religious Jihad.
People do get extremely strongly motivated on idealistic issues.
It is better to demonstrate the fitness of your worldview by the quality of your code that the loudness of your dogma. Another strong motivator is practical experience that the process works better than closed source. Anyone who has the very next day recieved a fix for an open source program becomes a convert overnight. This forms a strong positive feedback locking people into the system. Evolution works on a very broad, but slow front.