""It is the prerogative of the human intellect to dominate the energies offered by irrational nature and to orient them towards an end conformable to the good of man." In regard to your question as to why the pill is so bad if it is permitted by the Church to be used sometimes and at other times it is forbidden. The answer is that the pill is not intrinsically evil, of itself. It is made up of varying levels of the hormones called progestogens and estrogens. There is nothing evil about these hormones; God Himself created them! Yet He created them with a biological purpose of giving the female body the potential for fertility . . ."
January 1, 1970
https://en.wikiquote.org/wiki/Hormonal_birth_control