I think it would have been better if they asked the public, " Is the JW's at your door a pedophile? " and add a bit more. Many people won't know what a Kingdom hall is so I guess the target audience is current Jws.
I am all for it. I think billboards are very effective as I said once before I recall in Texas on 635 ( LBJ for the locals) the Timothy McVeigh sign " Highway to Hell". Extremely effective and caused a lot of local discussion.