The grip that they have on people is very powerful, because there will be many like me- I did not come anywhere near anti-JW literature or websites until I was convinced I was out (which, in my case, is when I realized I did not believe in god). Once I allowed myself to look at information about the WTS, it was almost overwhelming.
It is much more difficult to shield people from that information today, since it is within easy reach and it's not easy to know who is reading 'apostate' information. Browse through a bit of JW history and you'll find more than enough info to show you that they are not what they claim to be. The amount of info (much of it from the WTS itself) is staggering. I think that most JWs are about an hour's worth of research from leaving, but it is very very difficult to defy the leadership and seek out this information.