People who are good people. People who were (in most cases) just trying to do all they could ... were looking into things to find out how to be better within their faith...
People do not suddenly become "bad" or "sinful" because they find that they no longer believe... They really don't. They are still the same people that you loved before, they have just found that it no longer works for them. Be that because they just find they are no longer inclined to go to church, or because they find information that doesn't jive with the things they were always taught, or even because every time they go they end up angry.
The best way to make people "Anti" is to ostracize them and make them feel judged.