It's conceptually pretty weird to have a mental model where the single vote that brings one side to 50%+1 implicitly flips millions of other votes.

It makes sense when you consider those millions of other voters are apathetic by definition. They can be implicitly flipped like that because they, supposedly, don't care at all. If they did care then they would vote and then wouldn't be subject to that. And that is why it is vital to be extremely careful with apathy, in all aspects of life. Because apathy is a choice.

You leave it to others if you choose not to vote, yes, but you didn't vote, neither implicitly nor explicitly. It doesn't allow one to add you to the tally of voters for yes or no as the person above did