I am not surprised by Liberman's reaction to Kilpatrick, given that Liberman seems to be a defender of grammatical anarchy. Liberman tries to justify his anarchistic approach to grammar by quoting from Friedrich Hayek's Law, Legislation and Liberty, Volume 1: Rules and Order; for example:
All of which is true, but misinterpreted by Liberman.
Man ... is successful not because he knows why he ought to observe the rules which he does observe, or is even capable of stating all these rules in words, but because his thinking and acting are governed by rules which have by a process of selection been evolved in the society in which he lives, and which are thus the product of the experience of generations.
First, given that Kilpatrick cannot dictate the rules of grammar, he is a mere participant in the "process of selection" which shapes those rules. In a world that valued effective communication, Kilpatrick's views would be given more weight than those of, say, a twenty-something who injects "like, you know," into every sentence. But whether or not Kilpatrick's views are given more weight isn't up to Kilpatrick. However much Kilpatrick might like to be a linguistic authoritarian, he is not one.
Second, Hayek's observation has nothing to do with anarchy, although Liberman wants to read into the passage an endorsement of anarchy. Hayek's real point is that rules which survive, or survive with incremental modifications, do so because they are more efficient (i.e., more effective, given a resource constraint) than rules that fall by the wayside.
Kilpatrick, and other "strict constructionists" like him, can't dictate the course of the English language, but they can strive to make it more efficient. Certainly the thought that they give to making English a more efficient language (or forestalling its devolution toward utter inefficiency) should be praised, not scorned.
Language games can be fun, but language is much more than a game, contra Liberman's approach to it. Language is for communicating ideas -- the more efficiently, the better. But, in the three posts linked here, Liberman (strangely) has nothing to say about the efficiency of language. He seems more concerned about James J. Kilpatrick's "linguistic socialism" than about the ability of writers and speakers to deploy a version of English that communicates ideas clearly.
Well, at least Liberman recognizes socialism as a form of authoritarianism.