I did not "make up" or "invent" this detail; it was included in the accident report. Your insinuation that I made it up to spice up the story is insulting and degrades the research that I put into this article. Please, please do your own research before accusing others of being sleazy.
Can we prove that this was the reason the pilots missed this critical detail? Obviously not (although the fact that the child interrupted them right before they were about to get to the point in question is fairly strong evidence). But air crash investigators all over the world, including the ones who wrote this particular report (which, again, specifically cited the distraction of the child in the cockpit as a possible reason for missing the info), have always had to venture into the realm of the speculative in order to explain human errors which lack clear causes. Safety is not improved by ignoring the possible causes of human error. A child in the cockpit distracting the pilots is an obvious potential source for error which cannot and should not be ignored if we want to make sure similar accidents don't happen again.