If you think of voice as the way YOU communicate so that even if you don't give someone your name, they know it is you by your word choice, sentence length and structure and the topics you choose. Voice allows you to express yourself in your own unique way, leading the reader to hear you as you write which is very empowering to the person speaking. If you think of silence as a way of empowering a person, imagine the quiet rebellion of those who practice civil disobedience to change laws they dislike without speaking to those who oppose them. Think of the silence of those who daily go to work in abortion clinics knowing that this could be the day someone attacks. Both voice and silence empower the person to influence the people around them; the choice of which to use is up to the person choosing. Third person makes you be the observer using he, she, they rather than the participatory I making you part of the action. In other words, you must describe rather than participate in the choice.