A code of ethics is backed by law at least for the most part (sometimes ethical and legal principles might even clash). And here is the biggest difference. For doctors or lawyers unethical behavior leads to losing the license to practice. There's no such thing for coding.
In principle (because the technicalities are way too complex to address here and now) there's no reason specific fields in programming couldn't require a license, like a clearance needed to work with sensitive data.
Coding is more and more used to build the backbone of future society. It's about time we recognize the criticality of the whole industry (not just the coders themselves). Having no ethics code for this is not very different from accepting when soldiers invoke the "superior orders" defense.
It may very well turn out that it simply can't be applied to this field but to get there you have to at least consider it first.
