The first is regarding compiling the kernel. This is seen as a guaranty, if things go wrong I can fix it. This plays on the idealism of youth, in which you have large amounts of time to track down and fix the problem, and the idea of I could if I wanted to! Examples of where this comes into play are getting a driver to piece of hardware X to run of older system Y. In the windows world if your driver does not work for new OS or visa-versa you are out of luck. You have to pay to upgrade. Where-as if it’s all open source you can just spend time porting the driver. Then share and save others time/money. The flip side is valuing your time more than your money, and just buying a new PC, or new Component or new OS so stuff just works.
The another concept I can think of is OSS vs. Microsoft is along the Alt.Net vs. MS.Net argument, where MS doesn’t embrace / leverage development tools and has to write it’s own. Often to the disdain of the Alt.Net crowd as they feel sidelined by MS and/or that MS has missed the point. It’s understandable that MS does what they do, but that’s because they are a commercial company. They build developer tools to push their platforms not tools for the sake of tools.
The last idea is, OSS is an idealistic stance, and people who have idealistic stances have an emotional attachment to that opinion, and therefore behave fanatical when their position is attacked. Just like religion really.