You expect a government worker to do math?
Obama’s campaign team kept tabs electronically to the individual level and had hordes of grassroots volunteers knocking on doors offering free rides, and enough money to buy out small countries. They only managed, what, 70% turnout?
Now consider, out of that turnout, maybe a third are Republicans. Meaning, they would have to out-do Obama’s success by a factor of close to 2.5 times.
I suspect a lot of Democrat votes and even some union votes went to Walker. Such would not have told any exit poller that, though, or any pre-poller, either. Exit polls are much less likely to be indicative of the real vote than in the past. Everyone is conscious that with the ubiquity of cell phone cameras and recorders and surveillance, their identities are open to these pollsters