For so many people, "building a safe AI" just pattern-matches to "raising a child so he becomes a good citizen", even though these tasks have nothing to do with each other.

Suppose you build an AI that exactly replicates the developmental algorithms of an infant brain, and you embody it in a perfect virtual body. For this particular type of AI design, the analogy is perfectly exact, and the AI is in fact a child exactly equivalent to a human child.

A specific human brain is a single point in mindspace, but the set of similar architectures extends out into a wider region which probably overlaps highly with much of the useful, viable, accessible space of AGI designs. So the analogy has fairly wide reach.

As an analogy, its hard to see how comparing a young AI to a child is intrinsically worse than comparing the invention of AI to the invention of flight, for example.