Even with the most advanced self-learning and reasoning AI, there was a human that ordered it to learn and reason.
same with kids: there were humans (parents, teacher, peers, etc.) who taught them to reason
the problem with your statement is: when the first sentient computer is built - your argument does not hold, because there was surely a human (most likely several of them) behind it
"An idealist is one who, on noticing that a rose smells better than a cabbage, concludes that it will also make better soup." - H.L. Mencken