I don't disagree that both main parties are just puppets performing for the same master, but voting 3rd party is still participating in the system they have designed with the same illusion of choice, which is missing the point entirely. Still do it if you can, it's literally the bare minimum, but don't expect it to achieve anything in its own right, because it won't.

The point of pointing out the illusion of choice is for people to realise that the whole thing is a sham - elections are theatre to keep the population from turning on those actually in control - the rich. Pinning all your hopes on elections and elected representatives in a system designed to work for the benefit of a group you don't belong to, is never going to help you out of it. This kind of thinking is still falling in to their trap.

https://web.archive.org/web/20230803021951/https://www.newyorker.com/magazine/2022/08/22/american-democracy-was-never-designed-to-be-democratic

https://libcom.org/article/capitalist-democracy-illusion-choice