That's not true at all. Even Alexis de Tocqueville discussed the value in not voting. It takes away the mandate from politicians. I don't think we live in a real democracy and I'm not giving legitimacy to fake, fully-Zionist elections. Direct action is much more effective and at some point our government will dissolve if the vast majority of people exit the optics of fake democracy.
Voting 3rd party sends a message: "be more like this 3rd party if you want my vote".
Not voting also sends a message: "I wont show up and vote, so just ignore me".