He makes the legal argument in more detail in https://blog.cr.yp.to/20251004-weakened.html#standards

The gist of it is that standards organizations like the IETF depend on a specific carve-out in US antitrust law (in order for it to be legal for American companies like Cisco and Google to participate in them), and that carve-out includes a specific definition of what "standards organizations" and "consensus" are. So even if the IETF uses different words to describe its processes, those processes still have to comply with the legal definition that separates a "standards organization" from, like, an illegal cartel.