Our brains tend to simplify things to help us understand the world around us. "Both parties are dumb" is rhetoric that you submit to when you don't really want to understand what makes them different, or what their agendas are.

I'm not saying people don't get fucked on decisions either party makes. It does in fact happen, but the world just isn't so black and white. We need to have the ability to criticize our representatives and hold them accountable, but right now I'd say there's a party that doesn't want any such accountability, and their agenda would put regular people further away from being able to take action.