If people have no faith in the democratic process, the effectiveness for voting to enact real change, or if they believe that the entire process is a sham, then they are less likely to vote.
If you discourage enough of the right people to prevent them from placing a vote in the first place ("one vote doesntdoesn't matter"; "both parties are basically the same"), then you have effectively hacked democracy without interfering with the process of voting in the first place. Congrats.