That's Chris Mooney's assertion, that it hasn't become associated with liberals in a monolithic way as it has with American conservatives, especially in the political sense:
just because denialism occurs sometimes on the left does not mean that in the U.S. today"“and particularly in mainstream U.S. politics"“it's predominantly a left wing phenomenon.
Mooney goes on to argue that the anti-science attitudes often embraced by the left, (such as anti-vaxx and anti-GMO) haven't been codified into the Democratic party the way rejection of climate science and global warming as a legitimate concern has become party line for Republicans. True enough. But does that make the anti-vaccination movement any less of a threat to public health and society? Because while their irrationality may not have infected the Democratic party, anti-vaxxers sure look like a potent, influential force to me. Yet if you read between the lines of Mooney's post, it sounds to me as if he's playing down the significance of left-wing science "denialism." I've argued that there is an equivalence between anti-science irrationality on the left and right, but that the former gets a free pass in liberal outlets. On that note, let me ask this. Which does more harm: the Washington Post for the occasional George Will screed against climate science, or the Huffington Post for the platform it frequently gives to anti-vaxxers, such as Jennie McCarthy?