I'm vegetarian (largely vegan), so if they happen to see me when I'm eating or otherwise ordering food, this is an early entry point into the ethics discussion. But far more often are the oft-asked questions: "what do you do?" or "what are you into?", both of which go straight into a description of optimal philanthropy. In either case, it isn't long before they start asking me why I speak so strangely when it comes to ethical issues.
If you haven't had the ethics conversation with me in person (or if you knew me before I fully fleshed out my views), then it would help to explain what I'm talking about. A typical exchange might go something like this:
New acquaintance: "So what kind of stuff are you into?"
Eric: "My main interest at the moment is in optimal philanthropy. I strongly prefer a world where charitable contributions get distributed rationally, so I do what I can to try and help determine which organizations have aims that make sense."
New acquaintance: "Oh, I get it. So you're into figuring out which charities are better than others. I've heard of that."
Eric: "I wouldn't put it exactly like that, but yes, I think you have the basic idea."
New acquaintance: "How would you put it?"
Eric: "I just wouldn't use the word 'better'; that's all. I mean, obviously some charities are indeed better at accomplishing their goals, but that doesn't make them better in the moral sense of the word."
New acquaintance: "Surely if they're better at accomplishing Good, then they're better morally speaking."
Eric: "For moral realists, yes; but I'm not a moral realist."
And this is where the vast majority of people will try to find a polite way of ending the conversation.
My moral anti-realism stance has caused countless numbers of otherwise rational competent people to think I'm nuts. To many educated (but not philosophical) people, moral anti-realism is just code for nihilism. Hell, even among anti-realist philosophers, the specter of nihilism informs many of their arguments. (Mackie, Blackburn, Timmons, Joyce, and even Rawls all endorse moral anti-realism while doing their damnedest to be dishonest about it, just to stay as far away from nihilism as they can.) So I guess it's understandable if the average new acquaintance I make will also make the same mistake.