Why does that matter? Why would someone be willing to murder dozens of people and make dumb math puns? Why is it worthwhile for anyone to speculate that when dozens of people are dead? What value does it bring to understanding the situation?PewDiePie himself draws a connection between Pi Day and PewDiePie. As in, he did it literally today.
Also, if there was any intentional, symbolic timing to when this was done (there probably wasn't), it's not to Pie day of all things but the Ides of March