Honestly sometimes I think every country should have its own Sinn Féin of sorts. Just a party that never takes its seats. Yeah, try calling it the "same thing" when you can't pass any legislation or form coalitions or get anything done because a third of the seats in the national legislature are literally left empty on purpose. Don't like it? Well, it's your problem that your party is literally less electable than No Representation!
In the US that would almost literally be voting in Republicans. They want the system to crawl to a halt, and critical functions are legislated to frequently sunset so they can hold the system hostage on a regular basis.
Well, good news, US legislature managed to dismantle itself with all the "checks and balances" and liberum veto filibuster. Now it's just a circus to play for the gullible to legitimize this oligarchic empire. It is no representation, one way or another and somebody should openly state it. The best the progressive caucus could do now is to walk out.