This is a common moral principle; it is found in, for instance, the classical Christian doctrine on homicide, where directly willed killing is (leaving aside war and capital punishment) categorically prohibited, but killing (even when it is a certain result, or as nearly so as practically occurs) incidental to some act with a different end is not categorically prohibited, but judged according to the proportionality of the risked harm of the act with the harm it was avoiding. (Self-defense doctrine in American, and some other, law is ultimately strongly influenced by this principle, though it diverges a bit from it.)
Of course If your definition of unethical doesn't require intent to harm then this is a meaningless distinction. Another Reason why labels are unhelpful.
That doesn't make any sense. If I directly try to eradicate the Jews I'm immoral, if my actions just have a second or third order effect of eradicating the Jews then I'm not? Most people probably use the direct vs second order distinction when it's themselves who are doing something unethical via second order effects but that's just to save some cognitive dissonance. If I know my actions have second order effects of hurting lots of people and I still do it that's unethical.
>In any case labels mean different things to different people in emotionally charged subjects. Which is why they don't have a place in honest debate.
Reality isn't an honest debate, reality is realpolitik. People are likely to be emotionally charged when they're told that it's okay they're being hurt because it's just a second order effect after all. Learn to deal with that emotion and argue against it, not make posts on the internet opining for something which never existed.