It may be difficult to believe in this era of omnipresent information and instant news, but I didn't hear about this story until yesterday. (I don't follow the news. I know I should, and I make spasmodic efforts, but catching up with the headlines is not part of my daily routine.)
All that can be said at this moment is that it's shocking. Truly shocking, in the sense that I wouldn't have believed it if I heard it as a rumour.
Of course, we have to wait for the truth to emerge about what actually happened, why so many children died, and why they were buried in a mass grave. Until then, I think it's best to draw no conclusions.