I know I'm going to be blasted for this but I don't think what you're doing is right if for nothing else than what it could mean for others. Like it or not parents have a right to say who can be around their children and who can't. I know many people here wouldn't want their parents to take them to JW events or even be exposed to that stuff. I do agree with you that you should be able to see your grand daughter, especialy since you are the better enviroment here, but the fact of the matter is that Chloe's parents are the ones that should say who their daughter can be around. If you win other people could be sued to make their children be available to their grandparents who are JW's or in even more dangerous cults.
Chloe's parents don't want you around. True, you are her GRANDmother but you are not her mother and the mother's wish is what should be honored. Parents have their rights, even when they're the wrong ones.