Right from the start, JWs cultivate an "us against them" mindset. Most people agree that there's a lot wrong with the world and they find it easy to agree that the churches should have done more to make things better. Nobody's perfect, so it's easy to find fault with politicians, businesses and the churches. JWs point to one church or preacher who's done something wrong and they paint all religions but their own as guilty of the same thing. Because the JWs have a Bible in their hand, householders are fooled into thinking that they're different from the other churches, especially when JWs repeatedly claim that they are. Family and friends might warn the householder about JWs, and that gives the appearance of confirming the JW warning that the householder will be ridiculed and frowned on for studying the Bible.
Though householders may be satisfied with their own church, they don't get the individual attention from a Sunday sermon such as JWs provide by stopping by regularly to promote their own religion and to condemn the rest. Nothing beats advertising to get the word out, and the WT Society knows how to get JWs to "advertise, advertise, advertise" that they have all God's answers while all others are of the devil.