Looking at the signatories, this is not a spat between one part of the political spectrum and another. It's a structural conflict btw people who built reputations with single-authored pieces and platforms that encourage solidarity (or thinking-in-groups).https://harpers.org/a-letter-on-justice-and-open-debate/ …
The letter seemed "right" to me in a generic way... i.e., it made general statements about illiberalism, without any attempt to quantify how prevalent or consequential these area. The set of signatories was quite interesting. But I have no idea what you meant by your framing.