Presumably the base rate of bad people in the human population does not vary greatly from country to country,
That's an empirical question. I wouldn't presume one way or the other on that issue until I had some data. (I would, of course, have to define "bad people" in some reasonable way that would work cross-culturally to gather my data.)
Well, if it is true that the rate of "bad people" does vary greatly from country to country, it justifies xenophobia, racism and a lot of other nasty things, potentially even genocide on a utilitarian basis. I take it as a given that it doesn't vary much primarily because the alternative is too horrible to contemplate. It would imply that people are not created equal (in a human rights context) and in particular do not deserve equal treatment. It really opens up a whole can of worms.
Oh, I see your concern, but I was thinking of cases in which, for example, one country rather than another has much higher rates of some kind of overt behavior that societies around the world generally agree is criminal (rape comes to mind) although the causation of the different rates is something that is malleable (e.g., attitudes toward women). I probably agree with you as to starting assumption about human nature in an idealized condition before societal influences start their work on individuals, but perhaps think (having lived in more than one country) that countries just might differ in social conditions that make criminal behavior more or less likely for otherwise indistinguishable individuals. This all gets back to the issue of what the definition of "bad people" is, as I noted in my first post to which you have kindly replied.
That's an empirical question. I wouldn't presume one way or the other on that issue until I had some data. (I would, of course, have to define "bad people" in some reasonable way that would work cross-culturally to gather my data.)