I think people discount the butterfly effect.

One small event sets in motion a series of events that create large change inside of a complex system. One example, from Reddit:

The Buffalo Bills barely lost a game in 1970 by missing on a bad pass for a touchdown. That loss allowed them to get the first pick in the draft, O.J. Simpson. OJ stays in Buffalo for awhile, meets his wife, then allegedly kills her. Then hiring Kardashians father to be his lawyer. They win the case, making the Kardashians somewhat famous. Then Kim drops the sex tape, becomes famous.
Edit: allegedly

This is striking until you realize the only unique thing about this story is that the facts are public. Every event is tied directly to the past through chains of events in this exact same way.

Maybe protesting and other political demonstrations have a more significant effect than we give them credit for. Or moments of kindness or integrity. One single act that seems small could change or convince one or two people and that could spark a revolution.