I don't know how much (if any) of a role the disfellowshipping and shunning played in this tragedy, but more than a few have speculated that a distraught POMI (physically out but mentally in) JW might decide to end it all in despair, and then decide to take his or her family with them to "insure they'll get a resurrection after Armageddon."
The Witnesses currently teach to most everyone who dies before Armageddon will get at a tentative resurrection after Armageddon under the "resurrection of the unrighteous" principle. I've read accounts of those who were told by their relatives that they'd be better off to take their children out back and shoot them than to leave the Truth™. And who hasn't heard someone say, "Well, at least he died before Armageddon"?
The Governing Body doesn't actually encourage murder to achieve everlasting life for a loved one, but their teachings do create an atmosphere in which mentally unbalanced ones could easily draw that conclusion. So they do bear a measure of responsibility, in my book.
I think they also realize now that the no blood policy is a gross misapplication of Scripture which they would love to distance themselves from. But they can't, because it would undermine their self-assumed "spiritual authority" and might make their followers wonder what else they could be wrong about. Never mind about the thousands of unnecessary deaths of sincere true believers and their children. Their image as God's Anointed Ones must be upheld! For this too, they bear a heavy responsibility.
Dad blame it, I hate this blanking religion!