D. H. Lawrence opens his 1929 essay on pornography and obscenity by claiming that there is no consensus of opinion regarding a definition of the former: "What is pornography to one man is the laughter of genius to another". And that, similarly, nobody knows what the word obscene means: "What is obscene to Tom is not obscene to Lucy or Joe" .
I suspect it's this line of thinking which lies behind James Walker's claim that "any attempt to define obscenity is itself obscene" , by which I think he means that the attempt to impose shared meaning (or common values) on the individual and their lived experience is something he finds offensive.
But I'm not entirely sure that's what he means: for by the logic of his own argument - which seems to subscribe to a solipsistic fantasy of purely personal feeling and, indeed, a purely private language - how could I ever be certain of understanding what he's saying?
The idea of a private language was, of course, made famous by Wittgenstein in his Philosophical Investigations (1953), where he explained it thus: "The words of this language are to refer to what only the speaker can know - to his immediate private sensations. So another person cannot understand the language." 
However, no sooner does Wittgenstein introduce this idea of a language conceived as ultimately comprehensible only to its individual originator - because the things which define its vocabulary are necessarily inaccessible to others - than he rejects it as absurd.
Naturally, there has been - and remains - considerable dispute about this idea and its implications for epistemology and theories of mind, etc.
Not that the validity or falseness of the idea will bother Lawrentians, for whom inner experience and (their own) singular being is everything. They'll simply repeat after their master: If it be not true to me / What care I how true it be  - surely the most intellectually irresponsible lines Lawrence ever wrote, showing disdain for facts, evidence, and reasoned debate and, ironically, opening the way for figures that James Walker certainly doesn't approve of ...
Arguably, Lawrence anticipates the post-truth world we live in today; one in which shared objective standards and meanings have dissolved into thin air; one in which Tom, Lucy, and Joe all get to define words however they like, à la Humpty Dumpty. Knowledge is confused with opinion and belief; fact is replaced with feeling; intelligence gives way to intutition.
It all sounds very liberal, but it isn't. Indeed, historian Timothy Snyder argues, post-truth is pre-fascism:
"When we give up on truth, we concede power to those with the wealth and charisma to create spectacle in its place. Without agreement about some basic facts, citizens cannot form the civil society that would allow them to defend themselves. If we lose the institutions that produce facts that are pertinent to us, then we tend to wallow in attractive abstractions and fictions [...] Post-truth wears away the rule of law and invites a regime of myth." 
If it be not true to me / What care I how true it be ... This could so easily have been tweeted by Donald Trump!
 D. H. Lawrence. 'Pornography and Obscenity', Late Essays and Articles, ed. James T. Boulton, (Cambridge University Press, 2004), p. 236.
Lawrence appears to think that a shared meaning or commonly accepted definition of a word is inherently inferior and that only the individual meaning of a word has poetic power and rich symbolism. Even the simplest of words, he says, never mind those that are complex or controversial, has both a mob-meaning and an imaginative individual meaning. And these two categories of meaning are, apparently, forever separate. The problem, however, as Lawrence sees it, is that most people are unable to preserve integrity and private thoughts and feelings become corrupted by those which come from outside: "The public is always profane, because it is controlled from the outside [...] and never from the inside, by its own sincerity."  Such thinking is, of course, completely untenable.
 James Walker, writing on his Digital Pilgrimage Instagram account: click here. See the post published on 13 April 2021, concerning Peter Hitchens and D. H. Lawrence's Lady Chatterley's Lover.
 Ludwig Wittgenstein, Philosophical Investigations, trans. G. E. Anscombe, (Macmillan, 1953), §243. It's crucial to stress that a private language is not simply a language understood by one person, but a language that, in principle, can only be understood by one person.
 D. H. Lawrence, Fantasia of the Unconscious, ed. Bruce Steele, (Cambridge University Press, 2004), p. 70.
 Timothy Snyder, 'The American Abyss, The New York Times, (9 Jan 2021): click here.