Not saying chrome isnt fast.. heck I'm using chrome right now.. it is fast... BUT....
It seems to me they are clicking the forward button and therefore already have loaded the page once before, meaning a lot of the data is stored in cache and will be substantially fast.
Not that I'm saying thats a bad experiment ... Cause in reality they are testing the speed of the browser and how fast it can render the page.. not the speed of the internet connection..
EDIT: Now after reviewing the video once more, I see that its not actually even a good browser test because its not loading html components and rendering the page, its almost as if its a picture of some kind.
Here is a picture
showing the weird loading:
Now I have actually ran rendering speed tests for multiple browsers and found chrome and safari to be the fastest, then it was firefox and then IE being the slowest. But this if anything just hurts their cause as its not even doing it legit.