I have seen a good deal of cults. Maybe it is just human nature to be curious about exotic religions. But what people involve in these cults don't seem to get is how it affects their children. Maybe that is in other religions also.  I have heard that Muslims like to train their children as suicide bombers. So apparently the problem of cults is not confined.

The best remedy for this is common sense reason.
The Rambam understood Torah as intending to bring to natural law. Common sense morality. 

The more reason is divorced from belief,  the more problems with cults we get.  When cultural relativism started in the USA, this provided the model for people to look for true values in all kinds of exotic places.

So what I suggest is to reunite Reason and Faith, Natural Law with Torah Law, This was certainly the approach of the Rambam. At any rate you can see why Lithuanian yeshivas are so strict to keep out cults and cult members. They would not have to be so careful if Torah was a secular discipline. It is because Torah is holy that the flies are attracted as to honey.

Every value has an opposite value. And when the positive value loses its purity it decays into it opposite. So when people use the Torah for personal motives, it causes the holiness of the Torah to leave it and in its place is unholiness.

I have heard that Germany is especially concerned with the problem of cults, but I doubt if they made much progress in understanding or dealing with the problem. And I myself only became aware of my own weakness in this area recently. It is a hard problem. I have suggested before the idea of Rishonim. That is if you are Jewish then the best place to learn about it is books from the Middle Ages before cults became a problem and the emphasis was to combine reason with revelation. I suggest that this applies to Christians also. That is to go back to the Middle Ages and read the source material from that time --like Aquinas etc would be the best approach. I got this idea in my first yeshiva and I think it is  the cure for cults. [That is go back to medieaval sources.]