Why did Nietzsche Sternly criticize Christianity?

Answer 1

Because he stated, when post roman society was started, laws were based on general christian and Jewish teachings in the western society. He said however, in the 19th century (his era of promminence) that people do not care so much about morality and are not God fearing, therefore there is no need for religion and rejected it.

Answer 2

Nietzsche criticized Christianity because he saw it as promoting values that he believed were life-denying, such as meekness, humility, and self-sacrifice. He also felt that Christianity's emphasis on sin and guilt led to the repression of natural instincts and hindered individual flourishing. Nietzsche believed that Christianity weakened the human spirit and stifled creativity and self-assertion.