What he means is the reason they don't feel like they were lied to is because "most" people knew he was lying right from the start.

They agree with Bush that talking about dangerous WMDs after 9/11 was simply the easiest road to take towards a war with Iraq, even though it was basically unfounded.

Of course you still have people like Barg and Garrion going "huh? but.... but... you mean there weren't WMDs?" over the whole thing, but for the republicans "in the know," they understand that it was simply bending the truth in order to further the "roadmap for peace"

DGF, in this case, is taking pride in the fact that he was able to realize that Bush was not lying to *HIM* about WMDs (because he knew better), Bush was merely lying to the general "lower" population about WMDs.