They are sometimes called token reflexives. Sentences with indexical terms in them also have indexical truth values. It is not the name of any particular person. Other examples are 'here', 'now', 'today', 'Wednesday', etc. He makes the point by exploiting a crucial ambiguity in Classical Chinese.
All terms are relative to a language and to the local conventions of use.
Zhuangzi, he argued, allows the former, but not the latter. But absolutisms are points of view as much as relativism is. From our relativistic view they may look silly, but it is not clear that they are doing anything much different from what we are doing when we make judgments. Again we get a classic Zhuangzi double rhetorical question. Think of it as the point from which all guiding discourse emerges.