AlphaGo was only initialized by mimicking humans. It then played millions of games against itself. And learned what moves were more likely to lead to wins. And

AlphaGo was only initialized by mimicking humans. It then played millions of games against itself. And learned what moves were more likely to lead to wins. And then it was combined with a tree search algorithm that let it explore many more moves into the future than humans could consider. Training a bot just to predict what move a human would make, would always lose to that human. It will just absorb all the human's mistakes and weaknesses. And on top of that it will add it's own, since no AI algorithm is anywhere near 100% perfect.