I find that the biggest turn on for new age religions, and other forms of spirituality seem to stem from their apparent metaphysical openness. While the popular images of Christianity seem to give off an air of being restrictive, intolerant, small minded, legalistic, and punitive.
God is often viewed as nothing but some Cosmic Superhuman reminiscent of the Pagan King gods, with a dictatorial air, with good and evil determined by personal preferences, and are legitimate only through being an unchallenged power.
The Fall of man is nothing but some punitive sentence for breaking a rule. The sacrifice on Calvary is nothing but a punitive loophole. Mans sinfulness is centered on the resistance to follow rules down to the letter, and disgust at people in power.
Jesus being truth means the exclusion of all other truths. God is the king god to the exclusion of all other Gods. And the Uniqueness of Christianity being a revile towards other religions.
With morality, sex and the body are seen as evil, prohibitions against idolatry are sectarianism, evil is seen as a breach against some rules, righteousness is in keeping the rules, and being a member of the Church as some type of Cultural conformity.
Obviously none of this is true, let alone biblical. Nor what the Early Church actually believed, or even generally does. CS Lewis has made great efforts to refuse such silly superstitions. Likewise in the Chronicles of Narnia and Lord of the Rings, we are given the Gospel story told without any legalism and punishment, and a heavier focus on magic, mystical, and psychological themes. Which seems like popular new age themes also.
Yet I cannot help but wonder what happened that caused Christianity to be practiced in such a reductionistic way. Hence part of the scorn by Philosophical Atheists. I understand many believe its the doctrine of Eternal Damnation, that by default reduced itself by excluding people. Plus there is the belief that the Anselmian theory of Atonement may have caused it. Others look to supernatural sources like the Devil as making an effort to slander Christ. Others even see it as a personal egotism that wants to see truth as something systematizeable, and therefore cannot understand the deeper nature of theology, and only being mere models of reality.
For example, when Jesus says that he is the truth, it does not exclude all other truths, but is a fulfillment, not as a new idea, but absolute truth. Considering how all religions and philosophies have offered some truth, but cannot really give intellectual answers to what the truth is. For example, Buddhists understand that attachment and identification with the material world lead only to suffering, and the best he offers is detachment. Or the Gnostic understanding that it is true that God is not a human person with a human ego, but neither is he impersonal energy, being, or archaetypes. But no one can really explain Gods personhood, without falling into humanizing God, or depersonalizing him.