What are you helping to stop when both candidates are terrible? You're helping in the same way that "thoughts and prayers" helps people. You're simply participating in a rigged game and thinking that your participation is some sort of moral choice and "doing the right thing" when in reality that feeling is just self-gratification.
If you think you're helping, why does the political landscape continue to devolve and slide further to the right regardless of who wins? Why are more and more people becoming poor and homeless while a handful of companies and individuals are reaping all the rewards? That's the trajectory you're arguing to help maintain here.