Comments run on Giscus, backed by GitHub Discussions, which means a GitHub account is required to sign in and comment. That's a deliberate bit of friction, meant to discourage low-effort or bad-faith activity rather than to keep people out.
[Placeholder — write the rest of the actual policy here.]
[Cover: what kind of disagreement is welcome, what gets a comment removed, whether comments are moderated before or after posting, and how to report a problem.]