People are pushing many indepedent flavors of "anti-censorship" at the moment. Some of them clearly are dog whistle's for the alt-right by people who just want to say bigoted things without repercussions. The Substack version is more inline with the neoliberal complaints of censorship. This letter from Harper's Magazine[1] from a couple years back is a great example of this thinking. Whether the signees of this letter are "excellent writers" is certainly up for debate, but most of these clearly aren't alt-right thinkers.

[1] - https://harpers.org/a-letter-on-justice-and-open-debate/