As I've said before, the moral inventory of Step Four starts on page 67 with the question about our mistakes.
Before that, we have a general introduction plus an assessment of resentment followed by steps to eradicate it.
Why? Because we can't look at ourselves squarely whilst we're still fulminating against other people, so the resentment has to go.
Often people do the writing but fail to (a) garner the insights (b) implement those insights to actually eliminate the resentment.
This is like gathering the ingredients for a meal but not cooking the meal and not eating the meal.