I don't think anyone doubts that Blair was at very least, economical with the truth - although the Chilot Enquiry cleared him of lying - and elements of the media are always trigger happy when it comes to military affairs, being as they still think Britain rules the waves. It's not propaganda though.
And we're talking about the Guardian's op-ed pieces primarily in this context; but it can't be propaganda if they're showing both sides of the argument, or if the side they favour is backed up by actual evidence, data, respected peer opinion, reasoned argument etc. Anyone is free to disagree with it, I disagree with Larry Elliott's arguments in the same paper but I read his pieces because I respect him as an economist and a journalist.
Propaganda is not just "what I disagree with". The Mail has put out some reprehensible pieces - "Enemies of the State", anyone - but I wouldn't describe that as propaganda either. Absolute rubbish, definitely, irresponsible, for sure.