I believe there is no need to account for the fine-tuning. If it hadn't happened, we wouldn't be here to ask the question. The best we can do is to assume that it happened through sheer chance. To ask why it happened is like asking why a fair coin landed on heads rather than tails. I see no reason for supposing that the fine-tuning was more than the chance outcome of a seriers of random events.

By the way, I appreciate your response to Dumb amateur astronomer's accusing me of arrogance.