I think it was to show solidarity to those people and for just one day to stop posting about privileged, first world things and to show support and recognition of the awful crimes going on. It’s like when someone is murdered here like that poor girl who was attacked on her run, everyone posted about it to show their support and horror. Yes no one in Palastine will see it and it probably won’t make a difference but at least we are trying and if it’s done on mass it will have a much bigger affect.