You're right in that it's possible that the silent majority doesn't exist.
But personally, the reason I believe it does exist is two-fold:
1. The "My vote won't change anything" rhetoric only ever gets expressed by left-leaning people.
2. Only left-leaning people require endless purity tests for their political candidates and will refuse to vote for anybody that they don't think is the perfect candidate. These are the ones that talk about being fed up for having to choose between the lesser of two evils, then look like a Surprised Pikachu when Trump wins.
But personally, the reason I believe it does exist is two-fold:
1. The "My vote won't change anything" rhetoric only ever gets expressed by left-leaning people.
2. Only left-leaning people require endless purity tests for their political candidates and will refuse to vote for anybody that they don't think is the perfect candidate. These are the ones that talk about being fed up for having to choose between the lesser of two evils, then look like a Surprised Pikachu when Trump wins.