My take on it is that it is like entropy. There are many more disordered states than ordered states, infinitely many more, in fact.
Consider a Ming vase. There is one way for it to be a 'good' vase, and untold trillions of different ways for it to be a 'bad' vase, one that it is not attractive and no longer holds water, or flowers.
Or the human body. There is one way to be healthy, a million different ways to be sick or injured.
Say that a 'good' person is one who obeys the 10 commandments. This is like tossing 10 heads in a row. The other possible combinations, where at least one tail is tossed (or one commandment not followed), represent all of the possibilities for evil. Out of 1024 different combinations, only one is 'good'. That's a lot of evil possibilities.
The potential for evil abounds.