Here's the difference: Evidence for the Holocaust is overwhelming. Evidence for global warming is not. When you read of a gathering said to address the problem of climate change, you're reading bullshit. Climate change is not a problem. It is a characteristic of climate. If you think you are certain as to the direction climate change is taking, you are fooling yourself. The science is not settled, and anyone who says it is, either is lying or doesn't know much about science, which is rarely settled. In science, there is no place for quasi-religious dogma.