My impression is that the computer is programmed to make the results come out a certain way. I doubt the person manning the phone has any control over it.
My theory is they want a certain outcome. So they program the computer to spit out questions in a seemingly random order, over which the telephone operator has no control. The computer will allow a certain percentage of "right direction" responses to come through in order to make it seem real. Once the operator inputs the "right way" response on all but the percentage that is to be allowed, the computer then puts out a supposed screening question. The operator inputs that data and the computer comes back with a sorry, maybe next time message.
I've done polling before, and though it was several years ago, from my experience I would say you're impression is false. That sounds like far too complex of a system.
In all likelihood, no matter what age you gave, you wouldn't have been in the "age group" they were looking for. It was just an excuse to cut the interview short.
I also have a hard time seeing what benefit ABC would get from polling such a narrow demographic. If it was the AARP it would make sense, but not ABC News. There would be nothing newsworthy from such a poll.