In Christianity authority comes from God and his representatives on Earth like priests, kings, and pope, and not from individual humans. Humanism is the one that asks each human what they feel and want to shape society. So you have the voter deciding what is best for the people and you don't ask God or the Pope. You go to each human and ask him or her what they want. You don't go anymore and tell people "Yes, you might think that and feel this, but you are wrong because there is a higher authority saying that you are wrong," like it was in the middle ages, and is in now Islamic theocracies.
teachings of the Bible are so muddled and self-contradictory that it was possible for Christians to happily burn heretics alive for five long centuries. It was even possible for the most venerated patriarchs of the Church, like St. Augustine and St. Thomas Aquinas, to conclude that heretics should be tortured (Augustine) or killed outright (Aquinas). Martin Luther and John Calvin advocated the wholesale murder of heretics, apostates, Jews, and witches. - Sam Harris, "Letter To A Christian Nation"