Because the "rules based order" is the opposite of international law. International law applies equally to all whereas the "rules" of the "rules based order" are made up and applied selectively as benefits the imperialist West. It is also never clear what these "rules" and "norms" are which the West loves to tout as opposed to clearly written down laws, and this allows them to suddenly "discover" new ones and do away with or ignore others that are inconvenient for them.