Dr. Shepherd seems to be a good communicator and spokesperson for Climate Change and when he says it’s not a “left right issue” I believe he’s leaving the door open for people who still question the science.
Dr. Shepherd might not want to alienate the deniers/skeptics. If he does it might push those people; who are still questioning the science, over the edge and could make them dig their heels in believing Climate Change is some type of hoax or conspiracy. It's easy to offend some groups of people as evident in this thread.
Sure we can goof on the ignorant idiot deniers here. But this is TD. Dr. Shepherd has a much larger audience that he must try to educate and who are still open to learn.
Got to give Dr. Shepherd credit for trying to educate some of these people and keeping that door open.