I've said it before, I'll say it again... The hidden societies of the classic DCU (The Amazons, Atlantis, Gorilla City, Nanda Parbat, Skartaris ect.) in this new DCCU should be aware of each other and have some sort of mutual assistance pact, a "Treaty of The Hidden" if you will. One that has been activated since the revelation of Superman's existence and the Kryptonian attack. Thus why the Crown Princess of the Amazon's and the King of Atlantis are investigating this new era in the rest of the world where alien protectors, super speed crime fighters and space patrol men are now coming out of the wood work. That's how I would handle it.