And as to the second part of your question, yes it does matter. He claimed it. People build their lives around it. Wars were fought and are being fought because of it. Personal cruelties and abuses are happening because of it. It damn sure matters morally if Christ was lying when he made his claims.
Why does it matter? People doing wrong will always find justification. While many atrocities have been committed in the name of Christianity, that was not often the cause but most often a tool of convenience.
I will agree that most Christians misunderstand and misuse Christianity. I try to speak out against such practices when they are observed. But that has nothing to do with Christianity. It is people misuing dogma just as folk have misued Evolution.
Aslan is not a Tame Lion