I agree with the spirit of the point, but I also think it is critically important to SCREAM into the air right now that actually yes we do agree on a whole lot more on the leftwing than rightwing people do amongst their lame circles of hate.
It is our vibrant arguments, passionate disagreements and loud messy divisions and categories that keep leftism from becoming an echo chamber, as you nod towards in putting it in parentheses as 'echo chamber'. Yes this is true and necessary to point out, but also the leftwing simultaneously and not in the least bit paradoxically agrees on way more than conservatives do. Don't mistake blind compliance with whatever dominant narrative is being broadcast at the moment (hating trans people, being afraid of an """"""""immigrant crisis""""""""", not believing in evolution?? (did that go out of style yet? (sorry I wrote this aside like lisp code))) for a group of people being in true agreement and solidarity.
Interview a bunch of conservatives individually and ask them basic questions about how their espoused values connect with real world policies, actions and circumstances and if you ask about ANYTHING that isn't the hot topic right now to hate on in conservative circles you will get a random mix of complete and utter amateur speculation and shockingly silly re-imaginings of things that already exist because of problems that have already been solved (i.e. naive libertarians).
Interview a bunch of leftist individually and do the same thing and you will get basically the same damn answers every time on the important stuff.
Is healthcare a human right?
Yes
Does everybody deserve to earn a living wage?
Yes
Are all people created equal and worthy of empathy?
Yes
Does everybody deserve housing and the ability to live in a decent living situation?
Yes
Is climate change real and are humans driving it?
Yes
Do you believe in the seperation of church and state?
Yes..?
Do you condone any form of racism?
Emphatically no, never. I am an anti-racist which means also resisting structural racism not just overt racism
Are you a feminist?
Fuck off, why are you condescending me, of course I am
Is disability a weakness?
No, blind worship of strength is
Do you support LGTBQ+ people?
entirely
OF COURSE there are exceptions, but by and large do this to leftists and you will get a consistent expression of leftist ideology throughout their beliefs that agrees at a basic level (especially among younger folks) with almost every other leftist you interview, with massive exceptions in the details of course....
There are annoying and bad and toxic people on the left, yes, but let us remember we are much more effective at ensuring we are interacting on a basis of shared values, and we are much louder and much more annoying when people violate those basic values.