I'm curious what sort of procedures might use "stigma and fear" to reduce unwed teen pregnancy in poor women. If we take seriously the article CronoDAS posted regarding the rational motivations for young poor women having babies, then presumably addressing those specific motivations might do it.

While the motivations described to the article are in some sense rational, they're rational in an adaptation executor kind of way. Thus, other adaptations, e.g., the desire to avoid social shaming, can be used to contract them.

(Notably, we would not expect preaching traditionalist views via religion, or other means that did not change the material utility landscape, to work. If, as the article holds, young women choose to have babies on the basis of their material expected outcomes, then the procedures would have to alter the young women's material expected outcomes; and — to qualify as relevant here — would have to do so using stigma and fear.)

Compare the situation today with the situation 60 years ago. Notice what is and isn't different.

The same could be said for a lot of other views; that's scarcely unique to one end of a political spectrum.

So you agree that "stigma and fear" is in fact an effective way to change people's behavior.