"A negative goal is never a good way to live your life. It makes you bitter."
The FOSS movement can be compared to a liberation movement in an oppresive political regime. When people feel their freedom is too restricted some of the people have the need to do something against the oppressive regime. The goal here has nothing like a negative side, and doesn't make people bitter, on the contrary, they get thrilled by the higher value of their actions, and by the fact that they initiate a solution to their problem. As illustration consider the present events in the Arab world.
It's different from, say, the hate against a neighbor which would motivate a revenge. A revenge is rarely solving a problem, while a liberation does.