According to Zhuangzi, as I understand him in any case, all attempts to pronounce upon the nature of reality and how best to respond to it are subjective soliloquies. He would not, therefore, disagree with Guo's criticism of his ideas as being such. But Guo adds a pejorative modifier; they are merely subjective soliloquies; and this suggests that there can be something else, an objectively true understanding of reality (his own, for example). Here they part ways.
This 'merely' is defined as a failure to adequately deal with "the daily requirements of life". He chose to dwell in "a realm of mystical indifferentiation" and "a pavilion of unintelligibility". He "made dialogues which were really arguing with himself and have nothing to do with life."
So what? Let us assume Zhuangzi had his head in the clouds and contributed nothing to the politics of the Warring States in which he found himself. What is the ground for our criticism of him? We are required to contribute. Required by whom? Required by what moral principle? Who brings this judgment, and by what authority?
I am loath to defend the practical dimensions of self-realization; it concedes too much. I’ll end this post with Fung Yu-lan’s defense of his own philosophy in this regard, but for the moment I will act defiant. Zhuangzi has been called an anarchist. As an individual human being, he proclaimed the freedom of the individual. His being an individual was his authority. He answered to no one. He pursued his way without regard to the opinion of others. And whether his way failed to transform the world or no, whether it met the expectations of others or no, he pursued his path as he pleased. He was obliged to no one. No one had a ‘moral’ hold on him. He understood himself to be free to think, do, and be as he wished. That this doing and being was expressed in acceptance of and a ‘going along with’ all he encountered, speaks for itself and need not be sullied by being offered as ‘proof’ for the merit of his way.
Fung affirmed the uselessness of philosophy and the epitaph that it is an “empty branch of knowledge”. And yet: “If philosophy can enable men to become sages, then this is the usefulness of philosophy’s uselessness. And should this coming to be a sage be the reaching to the height of what it means to be a man, this is the usefulness of philosophy’s uselessness. This kind of uselessness might be called the highest form of usefulness.” (The Spirit of Chinese Philosophy)
You can check out Scott's writings on Zhuangzi here.