But you have to remember that you aren't usually debating or arguing a point for the person you're talking to to change their tune, you are arguing for the onlookers.

So when you are making an overgeneralization that comes across as incredibly dishonest (unless anyone who says "the Jews" actually does believe that Average Joe Jew down the road is part of a global effort to control and/or destroy the world or its population) you are turning the onlookers against you.

But if you talk about the Khazarians, you'll incite a few people to start their journeys down that rabbit hole.