There are a lot of valid points here about the moral culpability of the leaders of this organization. But the reality is that it doesn't amount to defamation. You can't look at what the words mean as defined in the rest of their literature and then apply that to the mentally diseased quotes in yet some other piece of literature and patch it all together to amount to slander or defamation. You have to look at what they directly say about you, and they don't say boo about anyone except that you are no longer part of the org.
Besides, as someone pointed out an another thread recently, you have to be careful what you wish for. If you want it to be so easy to make a defamation case, how do you know that you wouldn't be liable to the WTS for defaming them? I have certainly seen material posted on this site accusing the WTS org of things that are impossible to verify and in many cases almost certainly false. Sue them for molestation, sue them for swindling Aunt Mildred out of her savings. But when you try to restict what others can say and teach, you are endangering the democratic right of free expression in the public squares of a free society.