I don't think the media is necessarily "on his side". When the media sticks to just reporting the facts, people interpret it as the media taking the other side.
Also, his approval rating never got up to 90%. It was in the 80s in the days after 9/11 (which was sickening) but it dropped pretty quickly, and by the time the Iraq war began it was back down to almost 50%. It briefly went up after the war started, but then kept going down and down until he finally left office.
https://www.pewresearch.org/politics/2008/12/18/bush-and-public-opinion/