It's worth noting that Al-Jazeera has improved a lot since its early days in 2002/2003. With the launch of their English news service they made a concerted effort to improve their act and become more impartial. They're still prone to inflammatory coverage, especially on their Arabic news service, but as I said it's a huge improvement over what they were before.
Unfortunately many people, both pro and anti-war, are still operating on the perceptions shaped by events seven years ago and they haven't noticed how much things have changed.