Here's a statement: "Jesus did not have to be murdered. It just wasn't necessary." Try convincing me otherwise.
Christians want to honour and remember Jesus because he died, not because he needed to be murdered.
It may help to redefine things here. There is the notion of the necessity of the
event of him being murdered, and the notion of the necessity of the
concept of him being murdered.
For those who honour and remember him for his death, it's because they believe it happened and it's important to them. They don't have to believe it was necessary. The concept is necessary. The event is less essential.
Let's say your father died on a particular day. Was it necessary for him to die on
that day? Everybody dies eventually, so no, he didn't have to die on
that day.
Let's say he was murdered. Was it necessary to murder him? Some people die naturally, some get murdered. Someone wanted to murder him. That's fine. But no, it wasn't absolutely essential for your father to be murdered.
But he
was murdered and now you're attending his funeral. The murder makes his death somewhat more tragic, considering that someone hated him so much to murder him. You ask, why, why him? You spend the rest of your life investigating.
You remember him for what he did for you, as well as what he meant to the world. You also remember him for being murdered, for having his life come to a violent end. The murder wasn't absolutely necessary, but if he hadn't died like that you wouldn't celebrate him in this way.
Not everybody has to celebrate your father's life and death. But those who do are doing it because he was important to them. It's a similar thing with Jesus.