While I don't believe that voting is required, I also don't believe abstention is required. That does not mean, however, that I believe that one can vote for evil candidates simply because they're the LESSER evil ... a grave error circulating far and wide (because people want to vote for certain candidates) even among Trads.
Yes, I agree that the voting system has been completely rigged and controlled, but I could go there and write someone in (as I did last election) where that doesn't mean that I believe in the legitimacy and fairness of the voting system, especially since I know my vote is just symbolic, since my writein candidate has zero chance. In casting that vote I would not be endorsing the system, almost counter-endorsing it, just as some people will do things like vote for "Porky Pig" to express their disdain for the candidates ... but I think that in any other type of scenario, where you're going around pretending that the vote mattes, putting up signs for a candidate, promoting the candidate, etc. ... if you're gonig that far, then I think that OP's points are well taken.