> I mean technically the election is a 100% accurate poll. You get data from every voter.

Actually an election is literally a poll in the sense of a sample, you are counting people at "polling stations" in order to gauge the public mood about who should be president.

When you see it that way, Nate Silver is predicting a sample of an unknown distribution, the "true" distribution of people's preferences.

The fact that you can only make one officially binding sample ("the voters") is a practicality, as is the fact that there's an electoral college that means votes have different values. The fact that turnout matters is another issue, a statistician might call it a sampling problem.