I think, Nicholas, that very many ex-JW anti-Christian screeds are the product of anger and shame at the fact that they believed so strongly in a complete lie. They only partially dis-believe it, though, and still carry around too many nasty mental habits from their JW days: they accept the JW's criticism of Christianity, they never investigate (or do not have the ability to evaluate) the central claims of Christianity, they attack Christian strawmen instead of real Christian arguments. They are wounded in many ways.
Because of these wounds and because they feel, with some justification, that breaking free of the JWs is a real accomplishment, they are prone to paint with a very broad brush. It's unfortunate, but the unstated thinking seems to be something like, "The JWs are a dangerous cult, and therefore Christianity is wrong." Which is not to say you've done that here. Of course, helping that point of view is the fact that many Christians are, themselves, as unreflective as JWs.
I'd offer this in response to you: You see a " fatal deficiency of being incapable of perceiving yourselves and what you hold dear in the clear light of reality," with respect to Christians. Yet you also see some as sincere and intelligent. There is a tension between these two things, it seems to me, and if you are bewildered by it, then perhaps you should resolve the tension.