There is nothing to back anything up. You either believe or you dont.
This is what stands out to me:
The cross was a sacred symbol well before Jesus
Easter has pagan roots
Jesus was not born on Christmas, and Christmas also has pagan roots
There have been many gods over the ages that have died and have been resurrected.
The stories in the bible were originally meant to be taken literally, but now even many devout Christians claim otherwise.
I make no distinction between Christ, Egyptian gods, Greek gods, or any other gods or religions in world history.
So according to you, to say that Jesus Christ died is plagiarism because many people have died too.

I suppose next you'll say that everything about Kennedy was plagiarized from Lincoln.
I mean...come on...look:
Both presidents were elected to the presidency in '60.
Both presidents were elected to the House of Representatives in '46.
Both were runners-up for the party's nomination for vice-president in '56.
Both assassins were born in '39.
Both successors were Southern Democrats named Johnson born in '08.
Both presidents were concerned with the problems of American blacks and made their view strongly known in '63. Lincoln signed the Emancipation Proclamation in 1862, which became law in 1863. In 1963, Kennedy presented his reports to Congress on Civil Rights, and the same year was the famous March on Washington for Jobs and Freedom.
Both presidents were shot in the head.
Both presidents were shot on a Friday.
Lincoln was shot at Ford's Theatre. Kennedy was shot in a Ford car; a Lincoln limousine.
Lincoln had a secretary named Kennedy who told him not to go to the theatre. Kennedy had a secretary
named Evelyn Lincoln (whose husband Harold's nickname was Abe), and she warned him not to go to Dallas.
Both Oswald and Booth were assassinated before they could be put on trial.
Lincoln and Kennedy each have 7 letters.
John Wilkes Booth and Lee Harvey Oswald each have 15 letters.
There are 6 letters in each Johnson's first name.
Booth shot Lincoln in a theater and hid in a warehouse, while Oswald shot Kennedy in a warehouse and hid in a theater.