I take the opposite view of non-voting, philosophically. I'm with George Carlin on that point. "If you don't vote, you're not entitled to complain!" Conversely: "I didn't vote, so I didn't assent to this shit."
To me, that reads out like, "Well, you didn't jump in on the riot, so you shouldn't complain about the busted windows." Both major parties (if you still believe they're at all separate parties) are corrupt shit-feasts. By voting for neither, I can at least hold my head high and count myself as not being a willing participant in the malfeasance.
For everyone other than @Admin. who have the same puzzlement, though, it's simple: Principled people object to unprincipled behavior. They object to the same set of behaviors in both parties, but not all of the unprincipled behaviors one would object to are displayed equally by both parties. So one party catches more flack for a given behavior than the other does.
For example, both parties are dick-deep in corporatism, which is fucking foul. But only the Democrats are hellbent on betraying U.S. voters with open borders policies, so Democrats catch more shit for that.
Here's a sterling example for you, @Admin. : Both Weeg and X are a babbling retard. (The same babbling retard, and I think we all know it.) But only X is a *caustic* babbling retard, while the Weeg character is a goofy and inoffensive babbling retard. That's why, while I mock and taunt both, I save the sharper barbs for the X persona.