The whole of your argument relies on logic and reason. If she thought a or b then c follows. But the nature of mental illness is just the opposite; there is no normal path of logic. Trying to submit her actions to the normal process of sequential thought is a false notion.
I too was a full time mom for many years, I know about stress, PPD. Our own experiences are not always a reliable reference in judging the actions of other. What was happening with A. Yates is something different than stress or PPD.
that may be true, but my point is I dont care. Do you really believe that anyone who kills a child thinks rationally or sane? I know I dont. Does that mean they should be justified because they think differently, and act upon those thoughts? I doubt it.