Endemic of the human condition for a a lot of us. Something went wrong could it be me? No, it can't be me it must be someone else's fault. In our culture we sue.
Yes this person really messed up and child lost it's life becasue of it. But we also love to point out how someone is a stupid moron who should be sterilized etc. Have you ever done anything really stupid? I have done a few things. Yes, maybe you didn't cause a child to lose it's life but you may have screwed up in a way that hurt other people.
You make a valid point. However...
Some decisions that people make - such as the one in this story - are REALLY far into the deep end of the stupid pool. A 2-year-old isn't an immobile lump of flesh. They move, wiggle, walk, run, crawl, and climb. At that age, they also don't have an understanding of what is and what isn't a dangerous situation. It's the parent's job to protect them from themselves. Based on the information presented here, this is a CLEAR case of parenting failure.