Just a quick point - it may already have been covered. If so, sorry - I am new here.
If JWs can now take blood components, where do they think the components come from? Don't they realise that someone has had to lie on a hospital bed for an hour or so whilst a pint of blood is taken from them? ("A pint! That's nearly a armful!" Tony Hancock) Even if they take one tiny, weeny blood fraction, someone has had to donate a pint of blood in order for them to have this fraction. If they are not willing to give blood, and in fact think it is wrong to do so, they should not benefit from the fact that someone else has donated blood. Either you take blood (in which case, you MUST donate it, no matter how small a fraction you take) or you refuse to take it. You can't have it both ways.
Just my thoughts
xxR