The thing is, the People of Walmart are NOT your friends. Friend groups are self-selecting, and you don't HAVE to be friends with anyone you don't want to. But you don't get that choice with democracy. Whomever you would disagree with most strongly, about the most things, has the same vote you do. And somehow, you've got to avoid killing each other.
And let's be honest, the vast bulk of humanity doesn't know the first thing about how to lay a sewer, and YOU DON'T WANT THEM TO RUN THAT.