You have to spoil your ballot of you want to not vote in protest.
Every ballot that is cast is counted, even spoiled ones. But if you don't cast a ballot at all, it cannot be counted and no one will ever know of your "protest".
The only valid way to protest by not voting is to spoil your ballot.
But why is uncommon for stem majors to proofread and use spell check?
You'd think these science-technology types would be all over that.