You can make it clear how you feel, but without behaving in a way that will scare the friend off and ruin the friendship. It's hard, and I sympathise entirely with what TheGodBen
says, that if you find something ethically unacceptable it can be foolish and distasteful to hide behind IDIC or "it's okay if it's you, so long as not me". That's distasteful. On the other hand, telling people up front that their ways are wrong and unethical is a perfect way to alienate them; not only do you lose the chance to subtly influence them, but you lose a positive relationship too. Is it worth causing hurt to them and you, and risk sacrificing the friendship? I suppose that can only be answered by each individual in each particular case.
Personally, I believe, in an example like this, that "the Jake" should make it clear that they don't and can't endorse or support what "the Nog" is doing. It's not a personal distaste for the Nog, it's just being true to your own values. So in this case, Jake could say "no offence, Nog, but I don't want to be in a situation like that again where I have to confront something so alien to my values. You're a good friend, so let's agree to avoid those situations when we're together?" If you phrase it passively but firmly - not "you're wrong" but "I can't accept this", it reduces the chance that they'll be offended - it's just your hang-up, as it were. And if they truly care about you, not only might they agree to avoid throwing in your face something that disturbs you, but they might, through their empathy for you, start to understand what it is about their ways that troubles you. That may not be much comfort - the idea that "maybe this will eventually cause a shift in their views" is pretty poor when you might want to say up-front "no, that's wrong, don't think/act that way". So again, I fully understand where TheGodBen
is coming from. But by my nature I prefer passive ethics to active imposing morality. Maybe short-term that looks cowardly or even like it's excusing or dismissing that which you deem unethical but long-term it's much more effective and respectful, or so I personally believe.
Again on a personal level, I've been in this situation myself. My personal view of the world and our people is often different from the majority view and the majority view often pushes my buttons and offends my personal sense of ethics. I know well the guilt that arises when you don't act to assert your ethical and philosophical beliefs, but I know too that people can be hurt, and hurt greatly, if you're not very careful in how you express yourself. I'm sure all of us agree that there's a difference between commendable defence of your ethics and crusade against others, but where the line is drawn...which of us can truly say?
This is a difficult issue, but the discussion is rewarding.