Most voters do indeed know what they want. In any election, well over 90% are going to vote for the same party they did last time. But it just so happens that

Most voters do indeed know what they want. In any election, well over 90% are going to vote for the same party they did last time. But it just so happens that those ~90% are divided both bitterly and evenly. Which means the election is going to be decided by a small percent of people. The former group is increasingly baffled by the latter, since the differences are so stark. It's hard to imagine what kind of person doesn't have a preference. I'd say that the OP is encouraging people to realize that the difference is very real and will have a significant effect on their lives. They are not addressing the large majority of people whose minds were made up years ago.