There's a percentage of people who don't vote because they can legally, but things like health or work prevent them from getting to the polls or mailing in a ballot (where mail-in voting is allowed).
But that's about 10% of the non-voters.
The rest are comfortable letting anyone win.
If you want to see real change in the USA, you need to vote.
Find the candidates in your area who are moving the furthest in the direction you want to go, hold your nose, and vote.
Sitting out the vote does nothing to help anyone.
In the US if you don't vote, most people don't assume you're making a statement. They assume you couldn't be bothered.
The politicians don't see your non-vote as a protest.
The Republicans party is counting on you to not vote. They need you to not vote so they can push Trump and his rich-people-first policies.
If you want to protest: VOTE.