Can one voice do anything?

I don’t think that one voice can move a whole crowd to action. Rather, it takes the efforts of tens, if not hundreds of people. At first, while unlikely that it’s only a single person, one person might see an action that stands against their moral code. Usually this is a trait in society that everyone is aware of, but no one actively acknowledges because it is taboo in a society.
If the paper is especially well written or enlightening, a small core of people will be willing to do something to fix that problem will read it. While the majority might look right past without truly understanding the problem, this small group will take action how they seem fit. This small group will recruit, sometimes secretly more and more people until the group has grown to a size large enough to reach out to the general population and affect their way of thinking.
The hard part of this process is keeping the message from becoming diluted. When only one person starts a crusade, there is a large chance that his or her method will slowly fade away. This can be seen in the efforts of the Communists in Black Boy. Marx had an amazing idea, but the group that is trying to bring his ideals to fruition lose sight of what is truly important.