There is one version of Christianity. The one in the Bible. You can criticize Christians for getting it wrong, but you can't Christianity for their misapprehensions any more that you can criticize cosmology for the fact that they believe the Earth is 6000 years old.
For the record, the sole New Testament verse upon which you hang your entire point says this:
τοις δε δειλοις και απιστοις και αμαρτωλοις και εβδελυγμενοις και φονευσιν και πορνοις και φαρμακοις και ειδωλολατραις και πασιν τοις ψευδεσιν το μερος αυτων εν τη λιμνη τη καιομενη πυρι και θειω ο εστιν ο θανατος ο δευτερος
"απιστοις" (apisteo) is "apostate." An apostate is someone who claims to believe something but really follows a corrupted belief. If there is any truth to this verse, it is the people misinterpreting the Bible who should be worried about it, not the people who never subscribed to it in the first place.
This verse is not about the kind of unbelievers who buy Sam Harris books.