Of course they "often" don't! We're dealing with statistics of group behavior. If pollsters are right that voting behavior is correlated with socio-economic/racial profile, then that correlation must also apply to the universe of former "nonvoters" who have become voters.
By the way, does anyone have an answer yet to my question: "does anyone know if the 'nonvoters' were asked whether they agreed or disagreed with the statement 'there is no significant difference between the two parties?' And, if so, what the results were?"
Shane Mage
"When we read on a printed page the doctrine of Pythagoras that all things are made of numbers, it seems mystical, mystifying, even downright silly.
When we read on a computer screen the doctrine of Pythagoras that all things are made of numbers, it seems self-evidently true." (N. Weiner)