He's got some good points, especially about the US Army's Ordnance Corps. They were the ones that forced the 7.62 NATO round on NATO, when the British had something much better in the EM1- EM2 rifle and cartridge series. (yes, I watched the entire video)
He's also right that the Ord. Corps tests of the M-14 vs the FAL were a complete sham. The US Army wanted the M-14 and lied about it's producibility among other things (it was supposed to use the majority of existing Garand tooling to manufacture - the reality was quite different) so as to make the FAL fail. If one wishes, one can read Hatcher's Notebook in which he describes the actual testing of the M-14 vs the FAL (I found the bit about the FAL failing winter tests where the M-14 passed most amusing

)
Having used FAL's in the CDN Armed Forces and shooting a civilian M-14 (M-305 Norinco) I can say that the FAL is better balanced, has better ergonomics, is about the same weight, easier to shoot, and most certainly easier to maintain in the field. Neither one is controllable on full auto as the cartridge is just too powerful and the rifle is too light.
IMHO the only advantage the M-14 has over the FAL is its sights, but those are just M1 Garand sights designed for accurate fire out to 1000 yards - which capability is only used by the best marksmen in the unit (designated marksmen) as the German Army discovered at the end of WW1.
The M-14 ISN'T a bad rifle, but there were much better ones available even for the average infantryman in the mid 50's.