Leaving the god question aside, as I am an Atheist I am not interested in talking about something that does not exist, but I believe that if what some call Love is "conditional", it is not really Love at all.
Jesus taught a Love that had no conditions, no ifs or buts. He did not say "Love your neighbour, but not if they are not a JW" did he ? The whole point of the Parable of the Good Samaritan was that you should show unconditional love to all, regardless of what or who they are, and within that "all" Jesus included Apostates.
I know JW's will point to various Scriptures written by Paul to justify their hateful treatment of those who have left the JW religion, but Paul was not aware of the actual Teaching of Jesus as outlined in the Gospels, they had not been written by the time he died. Apart form that of course, actually analyse the Scriptures JW's use and they are taking them out of context quite blatantly to apply them in the way they do.
They do not practice the way of true Love.