1, Nietzsche believes that morality is anti-nature[1] because he feels that every instance of morality being taught goes against the instincts of life. He envisions the Church as the founder of morality that uses its teachings to trap its followers enthralled by shackling them with this so-called morality. A morality that causes fear, uncertainty and the banishment of passion, to which castration[2] is the offered cure. This cure is normally brought forward to those too weak willed or degenerate to impose moderation in the pursuit of fulfilment of those passions.
2, It seems, however, for there to be a basis for morality being anti-nature, there has to be something for it to work against. This comes in the form of the spiritualisation of those base emotions it strives to eradicate. Morality, in order to be justified, uses false cause consequence, by saying that anything bad that should happen to a person was because that person deserved t, pushing that person to attempt a lifeless and passionless existence for fear of the repercussions. In this Nietzsche believes morality to be the poisoner of life.
3, Nietzsche addresses the father of morality, in his case ‘The Church’[3] that attempts to improve man, when in reality it actually takes man and turns him into something “sick, miserable, filled with hatred towards life, full of suspicion of all that was still strong and happy.”
4, Nietzsche also believed, in denying God and accountability, the world is actually redeemed. He also believed that the means used to attain the aforementioned moralities of man have been utterly immoral.
[1] Nietzsche, F., Kaufmann, W. and Holingdale, R. (2012). Twilight of the idols.
[2] Figuratively speaking
[3] Though it could really apply to all forms of organised religion that seeks to enforce a code of conduct or acceptable behaviours, Mosque or Temple etc