1) It's a battle about what 'Climategate' meant.

2) The muddiness of the whole debate is a demonstration of the difficulty of applying science to public policy. As such it runs along the same lines as the problems with the idea of 'evidence-based policy'. Science is a pretty humble tool when it comes to saying how things are - compared to both its power of discovery, and to how science is used as a badge to exercise power. This is so not least because understanding what science says is a very unequally distributed privilege.