Gifted but Lazy vs. Less Talented but Hard Working
I have to say, I don't think I could disagree with this more.
In my opinion, grading is largely about the extent to which somebody is achieving their potential through hard work. When it comes to testing, at our school we don't expect a 60 year old man to spar as well as a 20 year old athlete -- instead, we're asking ourselves, "Did this 60-year-old man's hard work result in a guy who spars really well for his age?" If we saw a lazy 20 year old athlete who was only sparring slightly better than that 60 year old man, we'd fail the young athlete and pass the older guy.
We have a fair number of older students (50+), a lot of younger students (10 and under), a number of disabled students (blind students, Down syndrome students, etc.) and the usual cadre of 20-40-year old fit men who rattle your teeth when you spar against them. Our judges are testing these people not against an absolute standard, but against their potential -- and lazy students never EVER pass.
At our school, belts are definitely not a measure of how gifted you are.