"Okay, so both parties are bad, but what else can we do other than vote?"
There are going to be a lot of disenfranchised liberals that have lost faith in electoralism. Rather than allow the people to fall into doomerism or denial, what advice would you give people who are realising that western democracies are broken and that voting for the lesser evil is impossible? What action would you tell them to take?
Seriously though, you just have to point out that both parties want this status quo
Most people want change, they just don't understand the framework of how we can achieve that change
These are the days when we as principled Marxists/Anarchists/Posadists need to stand up and point out that the disconnect between the will of the people and the actions of their government is intentional
That the wealthy and powerful have always acted in their interests as opposed to the good of all people and the world
It's only going to get worse if we don't