like being trapped in a time loop,

Yes... and you have decided to blame leftists for this instead of the political racketeers who invented and maintains this cyclical pseudo-democratic spectacle itself.

How liberal of you... you, a (supposed) "anti-capitalist."

You can't be a liberal and an anti-capitalist, Clyde - you have to decide which you're going to be.

“Voting doesn’t work, because you can’t fix an inherently flawed system from within the system.”

And they are correct.

“Voting is just part of the system of oppression by keeping people complacent from making real changes.”

And they are still correct.

In my memory this anti-voting/vote boycotting goes back at least to 2000 Bush/Gore.

Nope. It was a thing long before the Russian Revolution, genius - it's only you liberals that are now finding out how utterly hollow your "liberal democracy" truly is and always have been. Leftists have known that before Marx or Bakunin even went through puberty.

Now let’s say I’m completely wrong,

Yes. Let's.