What irony is there in mrs merriweather's insistence that helen robinson be forgiven?

In How to Kill A Mocking Bird, there was not something to be forgiven of Helen. She didn't do anything incorrectly. As she alludes to Helen's have to lead a Christian life for her kids starting now and into the foreseeable future, the dramatic irony in these expressions of the judgmental, Mrs Grace Merriweather are that Tom and Helen both have probably been far more Christian in their actions than Mrs. Merriweather has ever been. Mrs. Merriweather is the person who should look for absolution as she makes many uncharitable remarks about her maid and different individuals in the group.