Traditionally, Palm Sunday was dedicated to celebrating Christ entering Jerusalem and Good Friday was dedicated to remembering Christ’s death. However, church attendance in the US became more sporadic and fewer people were willing or able to attend mid-week services. This meant that many people would celebrate Christ’s entrance into Jerusalem on Palm Sunday, celebrate Christ’s resurrection on Easter, and completely miss out on hearing the story of Christ’s crucifixion.
Because of this reality, the writers of our current Prayer Book compromised a bit when creating our Palm Sunday liturgy. The resurrection without the passion does not fully tell the story of Christ’s sacrifice for us, and so we hear the story of Christ’s crucifixion on Palm Sunday.