It’s not really a moral lesson. It’s a philosophical theory that all children grow up to become their parents (the ones they were raised by) and that they will overcome their nature in favour of nurture. So the wolf being vicious and then immediately looking after an orphaned child and repeating the same affectionate behaviour and words with that child and then having that child repeat the same caring justification of violence, it’s all just a proof of the philosophy. It’s also why we tend to pick partners that mirror our parents unless they were horrendously bad.
The moral you CAN take away from this is to not bully others and not to underestimate people who say nothing and hold back. People who are silent all their lives, end up blowing up the biggest. It’s also a reminder to everyone that we should ALL take the time right after getting angry to punch and scream into a pillow to release our anger so we don’t go mass murdering people who piss us off!

What the??? How could this teach me a moral lesson like, respect others, don't discriminate??