Everything about the core of Jehovah's Witnesses lends itself to inaccuracy. From a bible with truncated passages and altered translation, to the name “Jehovah,” to the Egyptology spawning dates like 1914, everything about them is riddled with patchwork Band Aids to problems of their own creation.
Plus, as copy-cat religion, they fall victim to very basic, post-Reformation mentalities such as the way they view Paul, the books they assign to his authorship, the way they view the literalism of the Hebrew Scriptures, the way they take Jewish lessons out of context, the way they view the “inspired” collection of the bible books, and the extremely simple way they use the bible to separate themselves from everyone else... even condemning reading newspapers as it is “Satan's Media.”
And where they are most wrong? They demand allegiance to an organization without question instead of teaching bible education, bible history, or a personal relationship with God.
They have not been correct for a single day since their conception. And preaching such isn't really blasphemy... it's just easily provable lies – and that sounds more like a crime against humanity.