Some people seem to get very agitated when I talk about the responsibility people have to make the right choices and that despite all the wrongs within the WTS, people themselves have a role to play and some personal responsibility for the experience.
They may be an element of not wanting to face the fact that their loved one is making any kind of personal choice to shun them. Who can blame them. It hurts like hell.
But we have all seen posters who say that they have never personally shunned. It can be done.
I remember one poster likening it to (in the case of a parent shunning a child)watching their child drown without taking the risk of diving in and trying to save them. In other words the parent is protecting their own life at the expense of the childs'. Utterly unnatural.
Of course the shunning parent would counter that they don't personally care about living forever (and that they would willingly swap with their child)but rarther it is their love and loyalty to Jah that is the reason they shun.
Jah has plenty of children, he will be vindicated (or not)with or without you. On the other hand, maybe JW's should play fair - maybe Jahs laws should be broken, maybe he should loose, maybe he's not the better 'man'!
Why do they shun people? Clearly, for a high-control group like the WTS it's so that they can protect their membership
Absolutely, to protect them from 'ttatt' erosion as you say but also on a basic level to have an 'in' group you have to make an 'out' group, which is essentially what being a witness is all about - isolation from 'the other/the rest' its just notching it up another level.
Essentially though, I think people hand the Society as much power as they wish. Everyone knows the pioneer/elder who sees their d/f son all the time and who noone would dream of saying a word to.
Accepted that some congs may be worse than others but....
I know people who would not dream of shunning their family member, cutting only, as has been said 'spiritual ties'.
At the end of the day noone has been stopped from going out in service for not shunning a relative, the only command a JW should be worried about as I see it.
As the Manic Street Preachers song goes
"If you tolerate this, then your children will be next"