Global warming and the Nazis

One global warming 'denier' got tired of being called a denier so decided to fight back.  He said he would start calling  global warming people 'global warming Nazis' since they call him a 'denier' implying he is like a holocaust denier. 

Here is what the ADL said about him: "University of Alabama-Huntsville Professor Roy Spencer’s analogy of proponents of global warming to Nazis is outrageous and deeply offensive.  This analogy is just the latest example of a troubling epidemic of comparisons to Hitler and the Holocaust. It has become too common to use comparisons to the Holocaust and Nazi imagery to attack people with opposing views, whether the issue is global warming, immigration or stem-cell research."

source: http://atlanta.adl.org/news/adl-condemns-spencers-nazi-analogy/

Here is a quote from columnist Ellen Goodman:

Here is what the ADL said about Goodman: ......zzzzzzzzzzzzz

And it gets even more interesting. Here is part of a review by Thomas Sowell of the book Who Really Cares by Arthur C. Brookes: 

"What is the reason why some people are liberals and others are conservatives, if it is not that liberals are more compassionate?

Fundamental differences in ideology go back to fundamental assumptions about human nature. Based on one set of assumptions, it makes perfect sense to be a liberal. Based on a different set of assumptions, it makes perfect sense to be a conservative.

The two visions are not completely symmetrical, however. For at least two centuries, the vision of the left has included a belief that those with that vision are morally superior, more caring and more compassionate.

While both sides argue that their opponents are mistaken, those on the left have declared their opponents to be not merely in error but morally flawed as well. So the idea that liberals are more caring and compassionate goes with the territory, whether or not it fits the facts.

Those on the left proclaimed their moral superiority in the 18th century and they continue to proclaim it in the 21st century. What is remarkable is how long it took for anyone to put that belief to the test -- and how completely it failed that test."

source: http://www.realclearpolitics.com/articles/2006/11/who_really_cares.html

The book above studied how much of their money and/or time people gave to charity and conservatives gave more than liberals.  

So calling people who disagree with your beliefs about climate science 'deniers' as if they were denying the holocaust makes sense to people on the left but if someone on the 'right' does it they are offensive? and the ADL seems to agree.