People reject the Bible because it strengthens conscience, wounds pride, exalts Jesus, disturbs routine, exposes sin and demands obedience.
Hebrews 4:12 - For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.
Many people reject the Bible because the Bible is the only book that tells the truth about the world and mans fallen nature and about man's innate evil and desperately wicked heart, and man doesn't want to hear it, because, as most should be cognizant of by now, humans generally do not want to know the truth. Humans have a proclivity towards degeneration, destruction, darkness, dishonesty, deceit and manipulation.