I think your fear is completely ignoring that a lot of sociopaths don't do bad things because of the consequences. Not everyone avoids doing bad things because they feel it would be ethically incorrect. After the 2008 financial crisis would anyone have found it "Ethically incorrect" to steal a million in cash from Bank of America? Probably not, but you still wouldn't do it because you'd go to jail.
A sociopath can be reasoned with, just not on ethical grounds. "You can go to jail," "Others will figure out you did this," "If you are violent towards me I'll shoot you in the forehead" are all reasons that could deter the people you're talking about. And for most of them those are completely effective deterrents. "You will feel sad if you do this" isn't one you can use on them, but it's by no means the only deterrent from avoiding culturally agreed upon ethics.