I doubt coffeesp00ns meant anything like that. Hank Green and John Green often refer to what they do on youtube as a community, the "nerdfighter" community. They are really big on the whole community building aspect and have many very different project that partly owe their success to the fact there is indeed a very strong community of people willing to give anything they start a more than fair chance and support it all the way.

It has nothing to do with you personally the same way I would not consider myself in the Lord of the Rings community because I don't read/watch anything and am not interested in that universe. Nothing to do with age or interests or aspirations. Just the fact that i'm not into that stuff.

The fact you never heard of them, just means you're not in the community (yet) simply because you were not aware there is one :) And there are plenty of different people that consider themselves nerdfighters but their main followers are in the younger crowd. Not sure if it's because of the type of content they produce or simply the result of the fact that YouTube is their main medium.