BP oil company pushed the idea that our individual carbon footprints matter so that everyone can share the blame of what the fossil fuel industry has done.
The article discusses this, yes - along with how the carbon footprint is a good metric for individual consumption even if corporate propaganda abuses it.
The most significant difference individuals can make is to create political and legal pressure by voting and protesting.
I agree with you that political action is vital. I don't agree that it's necessarily more significant than personal action. Feminists used to say "the personal is political", and it's still true. How you act in private demonstrates your commitment to the values you endorse in public and gives your voice more weight when you speak your values.
If you reduce your personal footprint, but never talk about it or encourage other people to do the same, your impact is limited to yourself. If you reduce your personal footprint, and make your actions contagious by talking about them with people you know and encouraging them to do the same, you can impact many more people, encourage them to follow your lead and reduce their footprint, and then they can encourage others to reduce their footprint, and so on and so forth.
Limiting the damage from climate change takes collective action. And collective action requires a community, and a community requires communication.
If you assume you are a lone individual and your personal decisions have no effect on anyone else, it's easy to imagine reducing your personal footprint is meaningless. If you see yourself as part of a community, and by reducing your personal footprint you encourage others in your community to do the same, you can see how much larger your impact can be.