The fact his name is used so fluidly in a political context, to describe things Orwell supposedly wouldn't like, only heightens the sad irony of its rhetorical fate. As an essayist, Orwell railed against and lampooned the tropes of contemporary political writing. In Politics and the English Language, Orwell lamented the use of ill-defined buzzwords like "bourgeois" and "totalitarian":
Words of this kind are often used in a consciously dishonest way. That is, the person who uses them has his own private definition, but allows his hearer to think he means something quite different. Statements like Marshal Pétain was a true patriot, The Soviet press is the freest in the world, The Catholic Church is opposed to persecution, are almost always made with intent to deceive. Other words used in variable meanings, in most cases more or less dishonestly, are: class, totalitarian, science, progressive, reactionary, bourgeois, equality.
"Orwellian" conforms to the phenomenon he observed in his 1948 essay, Writers and the Leviathan, in that it's a totally one-sided word, something people only ever use to refer to other people:
Almost everyone nowadays, even the majority of Catholics and Conservatives, is "progressive", or at least wishes to be thought so. No one, so far as I know, ever describes himself as a "bourgeois", just as no one literate enough to have heard the word ever admits to being guilty of antisemitism. We are all of us good democrats, anti-Fascist, anti-imperialist, contemptuous of class distinctions, impervious to colour prejudice, and so on and so forth.
If there was an "Orwellian" or "Big Brother" of his day, it may have been "fascism." From the author's 1944 piece titled What is Fascism?:
But Fascism is also a political and economic system. Why, then, cannot we have a clear and generally accepted definition of it? Alas! we shall not get one -- not yet, anyway. To say why would take too long, but basically it is because it is impossible to define Fascism satisfactorily without making admissions which neither the Fascists themselves, nor the Conservatives, nor Socialists of any colour, are willing to make. All one can do for the moment is to use the word with a certain amount of circumspection and not, as is usually done, degrade it to the level of a swearword.
Does it matter that "Orwellian" has become a conveniently meaningless cliché? Orwell's literature says yes. The destructive power of squishy political language was at the heart of Animal Farm, as the sinister shift of the slogan "Four legs good; two legs bad" to "Four legs good; two legs better" over the course of the novel shows.
Then again, that a public intellectual's name would come to represent a hazy collection of things he opposed might not surprise Orwell. Over and over again in his career, he pointed out how writers and orators exploited terms that seemed erudite, using their veneer of credibility to prop up otherwise unpalatable ideas. It's a practice that people today might call... well, never mind.