On the one hand, in context, it makes a little sense; you can understand it as saying that objective reality is an orthogonal concept to political extremism.
On the other, it's hard to imagine an "extremist" who's "in the middle".
I suppose you can picture a few things though:
1. A "delusional centrist". Here you get the severed connection to reality, but also the political moderation. Some "End of History" person with 90s-era thinking might be like this -- maybe what you think of when you hear "Krugman" or "Fukuyama" (though I think both have been shaken, actually).
2. A "radical moderate". Here, "moderate" is a little different from "centrist". I hear "centrist" and I think a Clintonian foreign policy hawk with liberal social policy; I hear "moderate" and I think more of a cultural stance. Nowadays "moderate" might connote breaking cultural taboos. It seems like male comedians end up in this category a lot. I don't think he'd use this description for himself, but I once heard someone describe Slavoj that way. "Radical" somehow connotes a connection to academia and to certain philosophers more than it does any specific conclusions (which may not be extreme at all).
Overall this maybe just what you get when you play with two words neither of which means a ton.