Pick the target, freeze it, personalize it, and polarize it.
He didn't have to "pick the target" in that case because the target picked him.
But notice how he froze the other party, personalized it, and polarized it.
He froze it by answering in a way that put them off their guard, by not accepting their premise and by forcing them to think for a second to figure out how to respond.
He personalized it in both remarks. By saying "people who think that believe there should be no private property" he took it out of the realm of ideological labels and brought it down to people, and the way people think.
His last statement, about "we're not going to turn the economy upside down so you can walk to work" both personalized it and polarized it. He personalized it by directing his remark at "you," by making it into "you want more low-income housing to help you." He polarized it by pointing out how silly the person sounded when their goals were stated in that way.
This just occurred to me, after all those years.
You know Tom, I don’t think many of us are as prepared as we should be to emulate Koch in that moment.