Man is born like a wild animal the Talmud tells us
Indeed living in Africa where people receive very little education and practically no moral guidance, we see this clearly in murder, rape; and in fact in people actually believing that power entitles them to do this – we need not look further than the President of the Country.
The bottom line is, that man is composite of two distinct souls, each driving in opposite directions, goodness versus selfishness, and all selfishness is able to rationalize its correctness.
So though man is good, nonetheless as he is also selfish and he usually is more selfish than good (for do the facts of human behavior – even amongst good people not abundantly show this?)
So for good people seeking to do good, they need to overcome their selfish side!
And it wont work to say “well I will just choose to do good” for the selfish side has more access to the mind than the selfless side; for as man’s desires creates his thoughts, hence the stronger desire in man will be the dominance of the thoughts, that will rationalize why selfishness should be done out of righteousness!
For example, imagine a person wants to give charity, and at the same time wants to go on holiday / vacation, his thinking will go something like this, “I would very much like to help that poor family, at the same time, in order for me to make money I need rest, if I don’t go on vacation then I wont have money to help anyone.”
Hence, it is only when man has a higher power, through adherence to his Rabbi, or his Rabbi to the law, that man can irrationalize the rationalizations.