> Monbiot ... is as far left as it gets

Not at all. See The Dangerous Cult of the Guardian by former Guardian journalist Jonathan Cook:

https://www.counterpunch.org/2011/09/28/the-dangerous-cult-o...

> George Monbiot, widely considered to be the Guardian’s most progressive columnist, has used his slot to attack a disparate group on the “left” who also happen to be harsh critics of the Guardian.

Media analysts Media Lens have written a lot on Monbiot too. http://medialens.org/index.php/alerts/alert-archive/search-t...