I love these videos coming out of JLab's Forstbite theater. They're hilarious and usually quite educational as well.
However, this time I think the "evidence" that they are using to show that light is a particle isn't that obvious.
Certainly their conclusion is correct that (i) no matter how bright (intense) the red laser is, it cannot activate the fluorescence and (ii) the green laser has a higher energy and thus, can cause the fluorescence, no matter how weak the intensity. However, all this does is show that the intensity does not correlate to the energy.
Now, if one understands the photoelectric effect picture and the Einstein's model, then one can see that this is ONE aspect of that model, which points to the photon picture. But this is just ONE aspect of the model. By itself, it isn't obvious from this experiment that light is a particle.
I think experiments such as the which-way experiment are the ones that would have a more solid claim of showing that light is a particle.