So, DC comics, animation that looks kid friendly. Characters that kids will be drawn to. It opens with kinky sex and a man masturbating to it... I wouldn't find it so inappropriate if they didn't use DC characters that are going to make kids WANT to watch it. And the worse part is that it is clearly doing its best to be something kids want to watch while also being inappropriately sexual. So despite the rating, its clearly marketed towards the under 18 crowd, it's clearly made to appeal to them.

Source on TMDB