What about if you're making a social media app, and the ethics are less clear-cut? It's not like you can show every new hire footage of Trump and drive home the negative impact of data mining/sharing--the causal link is tenuous, the viewer might sympathize politically, or they just might not care about politics.
Ethics in the abstract is very hard to teach; object lessons are easy.
It’s blinders. Plain and simple. I’ve worked with too many developers who will pander for money. A few that tried to shame me for not being on board (my life skills tell me calling someone a whore in a team meeting is a bad career move but it doesn’t stop me from staring at them and thinking it). When enough money is on the line principles get set aside. We like to think our cohort are above this sort of thing but the evidence clearly doesn’t support it.