There's an even more powerful counterargument to the facetious notion that "we all agree that murder/rape/slavery is wrong" than "people used to think it was right".
People today still think those crimes are right, as evidenced by the fact that there are many people who still do them. That's why we have laws against those crimes: to punish the many thousands of people who still attempt to carry them out, and in many cases succeed.
If we could "all agree that they were wrong", then we wouldn't need laws against those crimes, because no one would ever commit them.
People today still think those crimes are right, as evidenced by the fact that there are many people who still do them. That's why we have laws against those crimes: to punish the many thousands of people who still attempt to carry them out, and in many cases succeed.
If we could "all agree that they were wrong", then we wouldn't need laws against those crimes, because no one would ever commit them.