Would you tell people in China, "if you are disappointed with politics, vote in your People's Congress elections?"
If you have a one-party system, then all it means that the actual policy choices are made not by parties, but rather by factions or individuals within the one party, so if you want to change things, then the levers of change are obtained not by being a voter (or candidate) and having your party gain positions in the country but by being a party member (or official) and having your faction supporters gain positions in the party.
Why not vote? What is the advantage of that?
If you disagree with both of those things, voting has no positive and results only in negatives.
Also any changes that come from those institutions follow the real progress that gets made by common people.
"A wise man will not leave the right to the mercy of chance, nor wish it to prevail through the power of the majority. There is but little virtue in the action of masses of men. When the majority shall at length vote for the abolition of slavery, it will be because they are indifferent to slavery, or because there is but little slavery left to be abolished by their vote. They will then be the only slaves. Only his vote can hasten the abolition of slavery who asserts his own freedom by his vote." - Henry David Thoreau
I mean even in the DPRK, you can vote for whoever you want. Its what happens afterwards..
Does giving legitimacy to voting accomplish anytime? What about protesting the system by not voting, does that do anything?