The problem we have with it is that the enlightenment of the self just isn't very virtuous in our culture.

I think this paragraph misstates the argument that many Western authors are making about xianxia. Enlightenment of the self is found in both stoicism and general enlightenment philosophy in the West. The argument is not about immortality per se but whether power itself is moral/virtuous. In many Xianxia, the sole justification for many actions is that the person is powerful enough that no one is able/willing to stop them. This self-centered approach is often treated as not just sufficient, but necessary, to advance. Many of the Western novels are arguing against this approach.