You can find causes for causes all the way back in the chain. But voters are human beings with independent agency to act according to their own wishes. They have the ability to break the chain of causation if they want. And they don't. So it's their fault.

It's the same way that you can't say a child abuser isn't responsible for his crimes because he was abused himself as a child. Yes, that's a factor that contributed to his actions, but he's still responsible for his own actions no matter how difficult the decision is.

Yes, voting every 4 years is a democracy. It might not be direct democracy but direct democracy has serious problems and you probably wouldn't want it.