They asked me about why my comment was low rated... Pretty sure it ain't the left downvoting me.
But if you want to play the whataboutism game, I mean sure... I'm sure some of the handful of people here on left does it right back.. but that comparison is like a snail vs Goliath.
Which brings me to Politics_Too... I mean I'm not exactly a supporter of it, I generally do not go there, nor comment there.. but I think I get the premise behind it. This place is overwhelmingly republican and has been that way for quite a while. I tend to assume people on the left wanted a place where the power was on their side... so they created Politics_Too. I vaguely recall someone here who claimed that one of the people (or possibly the sole person?) who was involved in creating it was kind of bullied into doing so. I don't have any proof of that happening but it doesn't seem that far-fetched.
But anywho if you want to talk about air tight echo chambers, you should probably also consider that there is a group of people who looked at this stream and said you know.... the politics stream is cool with it's vast, vast republican majority.... But that just isn't enough.... So they created Real_Politics.... A stream which is so right-wing that it makes Politics look like Politics_Too.