My vote won't change the result of an election but I still vote.

Your choice definitely won’t change the course if you choose to contribute to the current course.

“Hey, this boat is sinking. Will this one bucket of water I throw out stop it from sinking? No? Guess I’ll just do nothing then. Maybe I’ll pour some more water in. That’s the way things are going you know.“

You may not change the entirety of your civilization, but you can at least be a part of a community that's living up to your ideals.

By making his choice he is changing society.

Lets say he has no global reach his choice may change opinions of the people around hom. It may even change minds on here.