Ethics are made up, so if you reach a conclusion that we're all pieces of shit and there's nothing to be done, you have the option to just rethink your system of ethics until it's sane.

Like, I'd maybe re-examine your ethical framework until it becomes an actually useful tool for figuring out what's the right thing to do in various situations. That's kind of the whole point.

e: Say, if your boss told you to shoot someone in the back of the head because he didn't want to deal with firing them. Would you say "Ah well... 'tis the way it goes under capitalism, amiright? Gotta pay the rent!". Nope, your line does exist, you just aren't showing your hand to us :P