yeah, i feel the same way. it used to be exasperation, but now it's more like pity. i just have to shake my head.
lately, i've been looking at it like this:
statistically, no matter what you come up with, someone will believe it. it's inevitable that there will always be 'fringe' groups of any religion, political structure, art form...whatever. usually it's completely benign, but even the truly harmful belief structures statistically HAVE to have true believers. i'm not saying that there's no hope for those that are currently JWs (that, unfortunately, they're fated to be diehards), i'm just saying that to aspire to "bring the WT down" is somewhat futile (at least on a large scale). there will always be true believers. i'm content with the 80/10/10 rule (in this case, 80% for all intents and purposes don't care, 10% are adamently opposed, and 10% are diehards). for me, this view takes away the exasperation when i seem to make no progress on my parents. i won't give up on them, but it's not worth stressing over because it's inevitable that some people will believe no matter what.