You say edgy, I say real and relatable.
As someone who's touched unimaginable depths of suffering in life, I found Mahou Shoujo Site thoroughly relatable and moving. It was truly a treat for me and I'd imagine it'd be a treat for anyone like me too.
Those that say MSS is edgy for the sake of being edgy have got this anime all wrong. Sometimes truly horrible things happen to at the hands of people who aren't so great and that's just reality for some us.
And if you're one of those people I 100% recommend this anime to you.