I find myself looking back more with pity than anger. I feel sorry for whoever brought the WTS into our families life. It's unlikely they did it maliciously and they were seeking to do the best thing for their family and their children. They failed, but then how many people really succeed at that. Many manage to do the worst for their offspring so there is something to be thankful for that we are not born elsewhere.
Why do you take it on the people who joined? I think that's blaming the victim of a scam for getting scammed. What's more, intelligence has absolutely nothing to do with the negative influence, the indoctrination and brainwashing that people get submitted to.
I am a born in, and during my time there in that organization I met and still now people who are quite intelligent and decided to join. Remember, one thing is the capacity for people to think and process information, another completely different thing is how a person feels and what their needs are.
The Wt and other cults capitalize on people's needs and feelings, not on reasoning or critical thinking. When you look at why people decide to join, their reasons have not a thing to do with knowing or being able to analyze a piece of information.