Orthodox Jews might find that some parts of his story hit a little close to home:
Anyone who attacks the church is either a suppressive person (2.5% of the population who are evil - think Hitler), PTS due to a connection to an SP (Potential Trouble Source - 20% of the population), or has committed various other overts and withholds (ie sins and secrets) and it trying to justify their own actions by making the Scientology seem less (because if you admitted to yourself that Scientology was the "one and only solution" then your otherwise small crime would have to weigh fairly heavily on your conscience).
It is also taught that if someone encounters the OT3 materials before being ready for them, then as part of the psychological conditioning to create "prison-planet" earth, the person may get sick and die and this is the reason it is considered "confidential" and heavily protected, and only available to members of the church past a certain level.(Zohar, anyone?)
This "truth" or "reality tunnel" is slowly conditioned into you until you internalise it. There is a huge taboo against reading or discussing anything potentially negative or "entheta" against Scientology or the church, often the taboo will extend down to the point that you feel it is wrong to "think" about potentially negative things regarding Scientology. To do so would potentially detract from Scientology and is thus a mortal sin against humanity, or you might wind up making yourself sick. I know this, because I was brought up within the church, and through the process of leaving the church and the Scientology "reality tunnel", it took me around two years to fully confront this internal taboo to the point I could openly think and speak on the subject.
Well back to the original question of do David Miscavage, Tom Cruise and the others running the Church, truly believe in what they say? My guess is that they do, they are so fully immersed in the Scientology reality tunnel, that they cannot actually see outside of it. Once you start questioning it, the contradictions become obvious and starts to crumble fairly quickly (it can be scary if you have nothing to replace with), so instead it is accepted 100% as a matter of faith to the point that they have dedicated the whole of their lives to this mission of "clearing" the planet, and "handling" anyone who gets in their way. There is too much at stake (the whole future of mankind) to even consider the possibility that they might be wrong or deviating from their course.