It matters to me personally that a small group of people have such a massive amount of power. It's already completely uneven regarding voting power - I can vote once in an election, but if I had a trillion dollars I could vote once, and then I could pay lobbyists, and fund advertisements, etc. I, as a single person or small group, with a trillion dollars, can have a massive influence.
This is regardless of how poor anyone else is.
No one should have this kind of money, it's really absurd.