There is a reason for why the WTS tells JWs to seek out people in a transitional or difficult point in their lives. It's because these individuals are in a psychologically vulnerable phase, and are more apt to be drawn in to the net of groups like JWs, Scientologists, Moonies, etc.
For my family, it was moving across the country and having no friends or family members in our new community. The JWs came round (just as they had in Calgary) but instead of shooing them away like they had in the past, they talked to my folks about how there was so much pollution in the city, and that pollution was something quite shocking to my parents. Next thing you know, there's a Home Bible Study™ at our house every week from The Truth™ book. The lack of close relationships in our new community, meant that the JWs soon became a source of social interaction, and there was nobody nearby with a vested interest in trying to snatch us out of the frying pan.
I wouldn't say my parents were idiots, but I would say that their vulnerabilities were exploited.