Wonder Woman is an empowering cinematic achievement, the lesson of which is that young women must be brave and committed to their beliefs if they are to achieve anything in the World Of Man. You Go Girl, Slay Queen, etc.
On the other hand:
So, perhaps the real lesson of Wonder Woman is that if a man gently criticizes a movie aimed at teenagers that you, a grown-ass-woman, like, well, you should immediately burst into tears, sobbing because WONDER WOMAN MATTERS. After all, if anyone dares disagree with your opinion on a piece of art it's a direct assault on you personally and an attempt to invalidate every single thing you hold dear and the only acceptable response is to get the vapors. Very Wonder Woman-esque, if you ask me.
OR perhaps the lesson of all this nonsense is that we are a ridiculous people and deserve every bad thing that is happening to us as a society.
One of the three, I guess.