I can see nothing wrong with Moondance. Nice little tune, although I've never played it out anywhere. Whether it counts as Jazz or not? Who cares? I don't recall VM ever claiming it to be Jazz.
Do people really hear a song and decide if they like it or not based on what genre they think it is. IMHO a good tune is a good tune wherever it comes from.
As to people taking against it (particulary here it seems), it's a victim of it's own success and popularity, as per Mustang Sally, Johnny B Goode, etc etc.