Deism that branches from christianity is called Christian Deism. It is one of the philosophical standpoint of religion. It refers to a person believing the idea of Deism (deist), who believes in the moral teachings but not in the divinity of Jesus.
Christian Deists often accepts revelation for it could be made to correspond with natural or rational religion. They adopt to the deistic religion and carries the values and ideals being taught by Jesus Christ while denying the idea of Jesus being a deity.
Christian Deists see no contradictions in those non-mystical teachings. The idea of the existence of Jesus Christ is still debatable for Christian Deists and the pure Deists. Some says Jesus Christ is a do exist and is a moral example spreading the words of wisdoms while others say He doesn't actually exist.
This is the first time I heard of this kind of belief. I can't tell for sure why people have this but i respect their belief but I will stand on what I believe also.