[Splendour]

Lebowski: And I guess that hatred is reciprocal since every group of believers claims superiority over everyone else on the planet.

Christians are specifically told not to claim superiority in the New Testament, but to practice humility. Religious groups are claiming divinely revealed truth which is an entirely different thing from superiority. In their zeal to teach the truth some may come across as superior and due to human nature there are some bad apples that have an imperfect understanding of church teachings that think they are superior, but its not the nature of Christianity to teach superiority. Christ said he came to serve.

Humility is a precept Christianity teaches to prevent people from claiming superiority and to continue to maintain the Christian's ability to see truth and to help unbelievers in recognizing truth. But the nature of man is imperfect, subject to temptation and ambition which translates into imperfect and self serving actions. That's why we have the saying "to err is human, but to forgive is divine."

There's also the possibility that a cult can offshoot and give false teachings. Christ said false prophets would follow him.

Edit: my bad, The New Testament also specifically teaches Christians to love. For God IS love. Probably even more than humility this is the central doctrine.