"It seems like everything in the manifesto boils down to #1 ("I will act according to my conscience")"

Yes

I think software engineering has reached this part of professionalism at many places. There, these specific codes of conduct are already in place (DO-178b, IEC 61508, ...).

But software is reaching more and more places and the barriers are lower every day. I believe that we need the discussion about ethics across all layers of professionalism.

This manifesto is of course not enforable. But it is meant as a basis for discussion.