If I was an abuser who wanted my victims to feel like they couldn't do anything, I'd try to convince them of some version what you just said.

Congrats! You decided to give up.

You're now advocating against your best interests and the best interests of everyone you love. Way to go, slugger!

Seriously. I'm as left wing as you can go and I still think that voting is useful to influence the system while building a critical mass of people willing to break the wheel. Saying "we'll never get class solidarity" is the most annoying and pointless thing someone can say so you have to assume they're working to ensure it is the case.