His opinion is fairly extreme, though if you read carefully and follow the links in that post you might conclude that some of his concerns are at least worth bearing in mind.
It's hard to characterize this movement that this article is critiquing, because it is diffuse. But I think it's fair to say that events in Syria and Iraq, and the anti-Russian stance taken by the liberal media, show that there is some consensus among liberals and conservatives in the US and UK around ideas that used to be called "neoconservative".
The basic idea is that liberals want to spread liberal ideas in Russia and other places, and realize that Europe is too tired of war to do this, so they conclude correctly that this requires more US power. Similarly, the neoconservatives would like to increase US power for its own sake, and the pro-Israeli elements would like to encourage the US to be more hawkish so that it relies on Israel as an ally more.
So the net effect is that both liberals and conservatives (of some kinds) would like to move away from a balance of power between the US, Russia and China, and move to a unipolar world where the US calls the shots.
It's hard to characterise the "movement" the article is critiquing because it isn't a movement, still less a neoconservative conspiracy against Russia.
(personally if I wanted to facilitate the spread of liberal ideas in Russia, the very last thing I'd do is boost US power to be a convenient bogeyman for Russians to unite against)
The idea that the Guardian is reluctant to publish anything likely to unduly upset multinational corporations or powerful Westerners - as expressed in the original article - is a bit hard to take seriously if you've ever read the Guardian.
The idea that liberals are actually part of some general movement to orchestrate a "move to a unipolar world" because they have the temerity to criticise Russian policy (as well as US policy, especially US interventionism) is lunacy.
You say "personally if I wanted to facilitate the spread of liberal ideas in Russia, the very last thing I'd do is boost US power to be a convenient bogeyman for Russians to unite against", and characterize my ideas as a "conspiracy", but how else can you explain how the groups I described united to support the Orange Revolution in the Ukraine[1]?
The liberals I'm referring to are certainly not especially critical of US interventionism. I'm not referring to Chomsky or even Bernie Sanders here, I'm talking about George Soros and his camp.
The Democratic party's National Democratic Institute, the Republican party's International Republican Institute, the US state department and USAid are the main agencies involved in these grassroots campaigns as well as the Freedom House NGO and billionaire George Soros's open society institute.
US pollsters and professional consultants are hired to organise focus groups and use psephological data to plot strategy.
https://en.wikipedia.org/wiki/Scott_Trust_Limited
Compared to say the Telegraph:
https://en.wikipedia.org/wiki/David_and_Frederick_Barclay
Or the Times:
https://en.wikipedia.org/wiki/News_Corp