They're freaking climate specialists. They studied climatology and research climate for a living. It's like saying, just because they dentists all went to dental school and believe sugar causes cavities, that shouldn't be given any weight just because they have a descriptive title of "dentist".

That little video you linked to is not current and leaves out the acceptance of computer simulations as a valid part of the scientific method.

This is from an article about how computer simulation is an accepted part of the scientific method within astronomy, but it is just as applicable to computer simulations of climate change and many other scientific fields such as medicine, meteorology, physics, etc.

From the 1990s to the present, the approach of using computer simulations for testing hypotheses flourished. As technology advanced, astronomical data sets became richer, motivating the need for more detailed theoretical predictions and interpretations. Computers became more prevalent and faster, alongside rapid advances in the algorithmic techniques developed by computational science. Inexorably, the calculations produced by large simulations evolved to resemble experimental data sets in size, detail, and complexity.

http://www.americanscientist.org/issues/pub/the-nature-of-scientific-proof-in-the-age-of-simulations/2

If every theory must follow the explanation in that video, a lot, if not most, of scientific theories of the last 25 years, in many fields, is invalid because computer simulations were used instead performing impossible empirical studies.

Edit: bad grammar, and I probably didn't catch all them.