The motif of harmful sensation - in other words, the belief that "memes" have an independent existence and spread like viruses - is on one hand another self-comforting masturbatory fantasy of the people who create memes. ("Poets are the unacknowledged legislators of mankind"? No disrespect to the Romantics, but only a poet could have thought that one up.) Workers and professionals in the intellectual/creative industries love to buy consumption goods which spread the message that "dreams shape the world", that "stories can change people's minds like magic", that all the world will dance to your tune if you figure out the magic word. Funny, that. A good marketing decision by Messers Gaiman, Stephenson and Pratchett - flatter your audience that they themselves are at least potentially kick-ass magic users.
On the other hand it's a kind of a distorted mirror of the way ideology actually spreads. It becomes plausible if you can cause yourself not to see the real social factors which determine which "memes" survive and which don't - that is, if you are a cultural "Wizard of Oz" determined to pay not attention to the force of Capital behind the curtain.
A hard law of the dialectic is that blind idealism always has a dirty materialist secret running in the background (and vice versa: Stalinism is the mirror image of this). If you seriously believe that "culture" is something which exists independently of material/economic realities, then it becomes easy to believe that North American and European capital dominates the world because of "our culture". (Although I wonder how these people explain China or Japan.) And it's a short step from there to seeing "alien cultures" as the enemy - which leads directly to "liberal imperialism". If you have decided that people are psychologically or culturally "sick" because, for example, they get offended by racist caricatures of their major religious figures, then it's all too easy to turn a blind eye when people with the right "culture" bomb the crap out of them and steal their oil. These people are like children and cannot be trusted with wealth or sovereignty.
The social liberalism of the new middle classes is also liberal imperialism - it consists of making up cultural excuses for acts of brutality carried out for the sheer naked greed of capital accumulation. Once again, imaginary solutions to real problems. The class position of the new middle class - their belief that symbols, language and "memes" are what is truly important - leads to their complete inability to defend people who are really up at the sharp end of neoliberalism and mass murder. They know deep down that their privileged position selling images and narratives depends on the exploitation and oppression which makes "manufacturing consent" necessary. The academic/publishing/artistic/infotech circles of this world are increasingly talking themselves directly into the Green Zone in Baghdad.