Only last week I got into a discussion with two of my coworkers (or cow orkers

) One by one, they argued about a dozen or two points (mostly the demonstrably false ones) that you listed in your OP. Both of them are
very politically conservative and that seems to be a pattern, at least here in the States.
The US has always had an undercurrent of "us vs. them" mentality that pollutes political discourse, and this has gotten even worse in recent years. A hypothesis that I have is that this philosophy has entered into public scientific debate as well. Toss in a propensity of some people to lump the whole of "the other side" into an exaggerated caricature boogeyman, and it is easy to subconsciously dismiss their arguments merely by their identity.
For instance:
"A/GW smells like environmentalism. eco-terrorists like Greenpeace are idiots. therefore, A/GW is wrong"
"I hate Al Gore because he is a liberal. Liberals are wrong about most everything. A/GW must be wrong."
"A/GW proponents think we need more regulations to curb emissions. I think that burdensome regulations are detrimental to the free market. Therefore, anything that may make regulations seemingly necessary must be wrong."
"Alarmists always exaggerate. Alarmists are bleating that we will be hit with a wall of water. Therefore, A/GW must be no big deal, even if it is real."
To be clear, I don't believe GWS think these things consciously and certainly not universally; I just wonder if, for some, this is a subconscious manifestation of the us-vs-them mentality and the human propensity to lump people into groups of ridiculous boogeymen. And I'm not personally immune:
When I hear arguments
against A/GW from the likes of Ann Coulter, Rush Limbaugh, Steve Milloy, Jeff Beck etc. (not sure if non-US folks know who these yahoos are) I am almost reflexively (and, admittedly, sometimes thoughtlessly) dismissive of them. So, I'm no better in that regard.
The Gnomon made a similar point a few posts ago, and I agree with his "too black and white" notion.