the decision to base your life on beliefs which not only can you not prove, but which, on the balance of the evidence, seem unlikely to be true, seems incredibly irresponsible. If religious believing had implications only for the individual believer, then it could be easily dismissed as a harmless idiosyncrasy, but since almost all religious beliefs have incredibly serious implications for many people, religious belief cannot be regarded as harmless. Indeed, a glance at the behavior of religious believers worldwide day by day makes it very clear that religion is something to be feared and justly criticized. “Houses built of emotion” is one thing, but beliefs that can lead to mass beheading for mixed-sex dancing, or the marginalization and victimization of gay and lesbian people, and the second-listing of women, is quite another, and it is for the latter that religious belief is justly held to require more justification

• Eric MacDonald

Even though this quote is focusing on religion, I think it applies to any beliefs people have that they think are "harmless" but greatly influence how they treat others. In short, since no person is an island, we have a duty to critically examine the beliefs we have that influence how we treat others.