"...ignored when making this decision..." Yep.
Then you're wrong. Period.
Seriously, how do you think we ended up with the 7.62x51mm cartridge? Remember, it's not just the rifle we're talking about here, but the cartridge. Why do you think the army specified the 7.62x51mm caliber -- basically just a slightly shortened .30-06 that paid lip service to the idea of an intermediate cartridge -- and refused to consider a truly intermediate round comparable to the British .280? Do you think it was a congressional committee or bunch of government bureaucrats who made that decision? No, it was for precisely the reason I said: hidebound, backward-looking military officers who refused to consider the intermediate cartridge, and insisted on trying to shoehorn an old-fashioned, full power cartridge into the assault rifle concept. These military personnel were the ones who then influenced the politicians in Washington to force the other NATO countries to toe the line on the issue of the standard cartridge, but it was the conservative military brasshats, not the politicians, who specified what they wanted in the way of cartridge and rifle combo, so to assert that their input was ignored is simply ludicrous.
The FAL beat the M14 in every test except accuracy. The M14 was adopted because it was American. The M16 was adopted because MacNamara's 'Think Tank' wanted it. In both cases, both the 7.62 and 5.56 were then jammed down other NATO country's throats with an 'Adopt it or we'll pull out of NATO' threat. There were several European countries working on cartridges better suited to European battlefields than a .30 cal cartridge that is just a .30-06 in a shorter case.
The Ordnance Board only makes recommendations. The politicians control the purse strings and have the final say. Same thing happened when the Trapdoor was adopted. Far more corruption in the 19th Century though.
You're simply not looking at the whole picture. As stated above, it's not just the rifle, it's the cartridge also.
And why do you think the T47 design, which became M14 was adopted over the T25 (which was, after all, another American design), or the AR10 (yet another American design), both of which outperformed the T47/M14? The answer is that both the T25 and the AR10 were odd-looking, futuristic designs, which displeased the conservative ordnance officers. Why do you think the military fitted the M14 with a conventional, drop-type stock, when it was also tested with a straight-line stock that gave superior control, especially in full auto fire? The answer, again, is that that resulted in an odd-looking, futuristic design, which displeased the conservative ordnance officers -- not politicians, military officers.
Once again, I suggest you read Ezell's book; it's clear you haven't. The fact that the FN rifle was foreign was not quite the obstacle you seem to think -- we'd adopted foreign rifles before, after all: the Krag, the M1903 (basically a Mauser -- we even had to pay the Germans a royalty for every Springfield we made), the M1917 (basically a Mauser with a British accent). The M14 was favored because it was a product of the Springfield Armory, which was a U.S. military arsenal. In other words, the army adopted it because it was produced by
their arsenal, and skewed tests against both foreign designs like the FN, and American designs like the AR10 that were not "in-house."
And while we did indeed jam the 7.62mm down NATO's collective throat, the 5.56mm
was not adopted because the U.S. military threatened "Adopt it or we'll pull out of NATO," we adopted the 5.56mm in the 1960s, and European countries kept the 7.62mm until the 1980s. There is no evidence that we planned pulling out of NATO during the Reagan era because Europe was reluctant to adopt the 5.56mm
