Must the Description of a Religion be Acceptable to a Believer?

Extract

It is a widely held view in the study of religion that the description of a religion must be acceptable to a believer. Belief in a thing, personal commitment to it, confers a kind of understanding of it which cannot be had by other means. Only the religious person knows truly what religion is. Similarly, only the Hindu knows what Hinduism is, only the Buddhist knows the true reality of Buddhism, only the Muslim has genuine insight into the nature of Islam, and only the Christian understands Christianity. Personal commitment or agreement gives a special access to the truth.