I am an atheist, but my understanding of the points raised is this -
Jesus was born a man, and thus felt all the temptations and fears that any mortal man would fear, including the hideous common criminals' death - crucifixion. It was for these reasons that Jesus was afraid and asked for the burden of this death to be taken from him, not as a part of God in heaven, but as a mortal man, knowing that pain and suffering were to come, and there was no escape.
The point of Jesus joining Man on earth as a man was to absorb all Man's sins and pay for them with his own death, thus allowing Man to enter Haven for all time.
I thiknk the idea that it was a 'PR stunt' is a little wide of the mark - Jesus was willing to die for Man, those who believe in God, and those who do not..