They themselves admit that a Witness must accept the entire range of Christian teaching "including those that are particular to Jehovahs Witnesses."--- Flock Book.
It is all or nothing. What many witnesses do is become de facto apostates by NOT accepting the entire range of teachings, but staying in because they consider
being a Witness better than being anything else. They are not interested in Truth, because if they were, then their whole paradigm would crack, as you said. It is
a house of glass, of cards, built on shifting sand. Only by DENYING the truth can a witness stay in. Emotionally and mentally I believe it is a heavy price to pay.