I mean that an election is (theoretically) an 100% sample because every eligible has the ability to interact with the voting process at the level that they choose. So the decision for some people to invalidate their vote, or to vote tactically, or not to vote at all, or whatever else: that's part of the act of taking part in an election. In that sense, you can't not take part in an election, if you're eligible to vote.
This is important, because normally, once you take a sample, you need to analyse that sample to ensure that it is representative, and potentially weight different responses if you want to make it more representative. For example, if you got a sample that was 75% women, you might weight the male responses more strongly to match the roughly 50/50 split between men and women in the general population. But in an election, we don't do this, because the assumption is that if you spoil your ballot or don't take part, that is part of your choice as a citizen.
But I think we're saying the same sort of thing, but in different ways: you can either see "the sample of an election is every citizen, regardless of whether they voted" or "the population of an election is everyone who voted", and in either case the sample is the same as the population, and we can therefore assume that it is representative of the population.
This is important, because normally, once you take a sample, you need to analyse that sample to ensure that it is representative, and potentially weight different responses if you want to make it more representative. For example, if you got a sample that was 75% women, you might weight the male responses more strongly to match the roughly 50/50 split between men and women in the general population. But in an election, we don't do this, because the assumption is that if you spoil your ballot or don't take part, that is part of your choice as a citizen.
But I think we're saying the same sort of thing, but in different ways: you can either see "the sample of an election is every citizen, regardless of whether they voted" or "the population of an election is everyone who voted", and in either case the sample is the same as the population, and we can therefore assume that it is representative of the population.