You're arguing for diffusion of responsibility, and we've seen it leading to outcomes that screw the whole society.
Engineers, as everyone involved, should definitely assess whether what they're doing is legal or even ethical. Not everyone has a choice, or the luxury to stand for their principles, but that's a matter of means, there needs to be a will in the first place.
Absolutely. I'm not sure where this idea comes from, that engineers should be compliant, neutral "implementers" who should just turn off their conscience and implement whatever pops up on their JIRA list without any kind of assessment or objections on ethical or legal grounds. That's not what people in a serious profession do. It's also so weird to hear this idea from engineers themselves! Like, are you really advocating to remove your own agency over your work??