I'm sort of validating your comment. Kind of.
xD I know what handful means.
"Small" is a subjective word. It only has meaning compared to the norm. There are some 7 billion people in the world. There are a lot of martial artists, and a lot of teachers. The point was that, to the source, "a handful" could really be a handful compared to the tens of thousands who have trained with or near other famous people.
They could not know at all how many people actually trained with General Choi, or how many are alive today, but still not be technically wrong by saying "a few". As long as the amount of people that trained with him was comparatively low to other examples (hypothetically, I don't know the real numbers - people or trained with Bruce Lee or Mas Oyama, or how many TKDers they're are compared to the amount that have trained with General Choi.), he could always call it a "small" amount of people and not be wrong.
In all likelihood, yeah, it's just shameless marketing. Or they could just be uninformed, or even
right, but accidentally misleading with their phrasing.