I think most people who believe things about Jesus believe him to have been what they want him to have been (not necessarily deliberately though). I don't think it's so much a matter of "proving" a theological point as just believing what fits in with their other preconceptions. Someone who believes that Jesus was divine, for example, probably believes Jesus to have been how they imagine God to be anyway, at least to some degree. At the same time, though, such people are typically constrained in what they can believe by church teachings, the Bible, etc., so it's not like it's a doctrinal free for all.