The point of voting is the provide the people with the illusion of choice. Its to pacify them into believing that the government is by them and is thereby legitimate. When you vote you are adding your voice legitimizing the existence of the state.

Now, the question remains should you vote to defend yourself. That's a personal question. I do not believe that is an effective means of defense. I reserve the right to change my mind on that but I have yet to see evidence that it is worth my time and attention.