First off, in some sense everything is political. Next, I am not claiming that you can't be supporter of open source while also holding a wide array of associated political views. My point is that the concept of open source fundamentally rejects the ideal capitalist conception of the world as a bunch of purely rational self-interested agents seeking to optimize wealth and economic output. Willingly performing labor for its own sake, for the benefit of others, with no expectation of return value, is obviously not capitalist behavior.