There are four men and a woman. Some of the men wish to have sex with the woman and so they agree to vote on it. The woman does not cast a vote. Did she consent?
Silence is NOT consent.
But not voting is not silence.
Not voting is the woman refusing to allow the decision of whether or not the men have sex with her be based on the majority decision and walking the fuck away. It is decidedly NOT consenting to the result of the vote.