Wouldn't be surprised if you also doubted man walked on the moon, jerk.
That's the iffy thing about that "freedom of speech", you're even allowed to have strange or rightout stupid views and opinions.
To bee serious, I'm sure some people in the "climate change"-camp also have at least simplistic views of the impact of human actions on climate. It is terribly difficult interactions in these coupled chaotic systems and climate change can even lead to colder weather in some areas. And on top of that, the whole thing isn't really understood as of yet. Nevertheless I think it would be a good idea to reduce the emission of greenhouse-gases as much as possible...
But I guess Mr Gore simply is a hate-object in some circles and then I know what I know about "haters". They would punch Mr Gore whatever happens. Strange people, indeed.