Isn't the reference and context backwards here?

As in, the "you should read Popper" comment was in response to somebody saying they though opting out of moderation/censorship was not good. I think Popper would broadly agree with this, and say that moderating out racism, transphobia etc is essential for good discourse.

This is all unfounded obviously, since Popper didn't ever use or write about social media.

Ah, an easy misunderstanding to make. The initial comment by ebisoka was not, in fact, in praise of the site's policy. The dog-whistle is the word "certain" near the end—insinuating that the Bonfire policy is to tolerate "racism and sexism" so long as it comes from minorities and is directed at the majority, following a quotation from the policies about how moderators may elect to ignore complaints of discrimination or inflammatory remarks when they are directed at majoritarian identities.

The CoC provides a justification for this decision—which, to elaborate on its rather simple framing, is that offensive rhetoric directed at minorities is qualitatively different from its inverse because it can incite racial violence and control the Overton window.* ebisoka doesn't consider this a worthy reason for the site's policies to admit to a biased moderation policy.

Note also that ebisoka began the post with "these sites are easy to figure out," which suggests there is a multiplicity of sites like Bonfire that can be summarized (and therefore dismissed) purely on the basis of their Codes of Conduct.

ebisoka put a lot of work into ensuring that post would slip by the radar for the average reader, but it's basically the same pattern of euphemisms that is guiding the Right's current crusade against DEI.

* Some strings attached. 1) Not as true in pluralistic societies or societies with near-equal splits; mostly a problem when the dominant group is vastly larger than the others. Hence other commenters remarking that this is a West-centric policy. 2) At the extreme end of the spectrum are places like South Africa and Zimbabwe, where the lingering populations of lower-class white people are subject to the double-whammy of lack of representation or advocacy in society and government, plus being the targets of resentment over colonialism.

ebisoka clearly came here to sow discord and pit groups of people against each other. Their comment history is very clear on that. What's really sad is that people took the bait right away.