Oddly, it's the power that it can be decentralized that is key here. As with any standing army that is ready to fight. It's not that the army needs to fight when the opponent has sufficient fear of it. In this case, having the full ability to go more decentralized at a moments notice can be sufficient deterrent for those who would abuse their power. 
Also, those who would abuse their power, in some cases, know enough to not provoke and instead to diminish it, making it seem unimportant in the hopes that it will fade and get forgotten. After which the abusers will resume with their intended goals. 
The power of open source means the code will live on after all of us, hence the reason to ensure the sharing of knowledge about what code there is, how to use it, what it is for, etc.