Why does democracy function as if Machiavellian principles married survival of the fittest? Why do we as a country lie, cheat, and bully to win power while hiding under the banner of truth, justice, and love? What is the end game?

Hedonism is good fit for your question.

An individual whats to live in a place where others live under the banner of truth, justice, and love. But, that same individual sees that by making compromises (lying cheating, bullying) they can improve their own situation as they see things. They don’t see this as compromising the society just improvements to their immediate surroundings.

The end game. Improvement of where one sees oneself. Small picture rarely affects the big picture. Brownian motion would indicate that just because a few individuals moving against the whole does very little as long as all individuals are similar in size. Of course, this changes as the individuals are larger or more influential but again it takes a lot to change course.