Refusing to turn out to vote in a Democracy because you don't believe in the system anymore - means you don't believe in the system - which is Democracy. What, exactly, is the alternative?
I think it is difficult to justify describing our representational Republic as a "democracy". It was founded on genocide and slavery, neither of which fit into the category. The reverence that the racists, misinformed and historically ignorant among the population have for its founders and their antiquated documents is a large part of our trouble.
No other nation, with the possible exception of our sister neoliberal imperialistic country, Great Britain, has the discord we have in simply defining its laws and foundational beliefs because they allow some flexibility and don't worship their founders as "divinely inspired".
When the white male falls from supremacy his gods will fall with him. You surely don't think that the future America, with a majority of non-white citizens, is going to accept the same pecking order inflicted upon them now, do you?
It was Democratic Governors that resisted the civil rights movement and Democratic cops that turned the dogs and firehoses on its protesters. It was also a Democratic President that allowed the beatings and spraying water on Natives on their own soil in freezing weather at Standing Rock, so don't sell the party on its "progress" that it has yet to deliver on.