I think Doc is a great coach. He's got a COY award and a championship on his resume. But the year he won COY, the Magic missed the playoffs; overall, his teams missed the playoffs 3 times and lost in the 1st round 4 times during the decade. In 2003, he only coached 12 games (going 1-11) before being fired.
I haven't reviewed the full resumes of the other coaches on the list, but those guys aside, Doc's resume doesn't stand out as being a consistently top coach over the course of a decade. Winning a championship one year may signify that you've figured out how to be a great coach, but it doesn't mean you've been a top coach all decade long. Imagine if you coached a team that failed to make the playoffs for 8 straight years and then you got lucky and won a championship in the 9th year - does that guy deserve to be on the coaches of the decade list? I say no. I'm not saying my hypothetical compares directly to Doc's coaching career, but my point is that you have to draw the line somewhere.
But again, like others have said, maybe some of the guys who made the list deserve to be there even less than Doc.