Why have Christians made the celebration of Jesus' birth mostly about the acquisition of material possessions?

Because to most people, Christmas is a celebration with friends and family and has very little to do with religion. People of many beliefs (and a great many atheists) celebrate it for this reason. Even most Christians know that December 25 couldn't have been Jesus' real birthday and that Christmas was originally a pagan holiday.

Easter is exclusively a Christian holiday.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.