DesirousofChange - "In the 03/15/83 WT which you quoted, they have rescinded that 'perverse acts' within marriage are grounds for scriptural divorce."
The WTS never "rescinds" anything.
Such a public statement would imply that they had made a mistake in the first place; and they'd rather gargle with broken glass than do that.
They just quietly and steadily tone down the rhetoric until it's gone, and then bump the matter in question off the list of DFing offenses in the Elders' super-secret handbook. It's an effective technique, and in many cases, the R&F doesn't even take notice until it's long gone (if they even notice it at all).
Actually, I should say it used to be an effective technique.
The rate at which WT policy dropped erroneous beliefs (as a result of empirical evidence that effectively refuted them) used to more-or-less follow the rate at which said evidence emerged (one example is the now-completely-debunked theory of "Flood geology"). The passage of time was on their side, and since the Big A was just around the corner, any mistakes would be moot before too long, anyway...
Largely thanks to the advent of the Information Age, however, empirical evidence, logical arguments, and direct experiences that successfully refute WT ideology are far more numerous and well-presented, and - more importantly - emerging at a breakneck pace compared to the WT's "Golden Age". An ultraconservative 20th Century high-control group simply can't respond and adapt at that speed.
I suspect it's another reason the rhetoric against critics and opponents (XJW or otherwise) has been cranked up to 11, recently; historically, high-control groups that feel increasingly more threatened than usual have a tendency to lash out in an increasingly unhinged manner.
IMO, the WTS is collectively fighting for its life (or at least, feels that way).