AA
But what makes you think they know they're wrong? (In regard to transfusion medicine)
JW opposition to transfusion medicine was born out of a misconception of what blood did in the body.
I've briefly documented the original objection here:
https://www.jehovahs-witness.com/topic/188572/jw-science-quote-2-5
Instead of rescinding the doctrine when the original premise collapsed, JW leaders and policy makers have reinvented it several times over the years, as the cost in terms of loss of face and credibility in admitting they were wrong on something of this magnitude would be enormous.
The arguments which have replaced the original premise have all been equally faulty and they know it.
For example, regardless of what anybody thinks of the NWT (It's not very popular here) an organization capable of any sort of translation would have known that invoking the partial predicate "Abstain...from blood" as in independent construction is ungrammatical. (I can elaborate)
Arguments about the sacredness of blood, misuse of blood, etc. cannot be reconciled with official policy, which currently allows a number of preparations and procedures involving blood. There's actually no single part of a transfusion procedure which is not allowed in other contexts.