Those other things like 6,000 year old earth are rediculo ad absurdam. You use them as frightening tales you'd tell children. Children don't want the bad man getting them anymore than you do. So you use those examples as warnings of what happens if you allow other things, like what you consider people who use non-scientific reasons to go against global warming. Even if you're right, it's argumentam ad logicam. It doesn't matter if the support is wrong, it doesn't make the conclusion.
2* 2 is 4 and 2 + 2 is 4, the reason is because addition and multiplication is the same. Just because the explanation is absurd, the person is right about both being 4. The far right evangelicals using "non-scientific" reasoning against global warming is a bullshit reason to use as part of your arguement why to believe global warming more. If you want to argue anything, don't use the aburd as validatation towards your arguement.