This is always a cynical exercise. As happens every year, it is a ceremony meant to bash Israel, and to pretend that Christians are equal to Muslims under Palestinian Arab rule.
The facts are that Bethlehem was a majority Christian city until it was under Palestinian rule, and Christians have been fleeing Bethlehem for years as Muslims harass and intimidate and force them out.
But PA prime minister Rami al Hamdallah said at the ceremony, "Despite the settlement activities carried out by Israel, the Palestinian people still believe in the culture of coexistence, brotherhood and peace that our Lord Jesus Christ has brought to them, and we call on the entire world to take a united stand to end the longest occupation and oppression of history. And the realization of the rights of our people and the recognition of its state, especially as the two-state solution is in real and serious danger due to Israel's persistence in its violations and its disregard for international law, human rights principles and signed agreements. "
The tree lighting isn't to remind people of peace on earth and goodwill towards men. it is meant to bash Israel, the only nation in the region that Christians aren't fleeing.