Let me focus on the first couple of objections (what is my work good for, given that there are many mathematicians far stronger than me). My answer is: your young colleague's activity is good and useful, at least in a weak, yet meaningful sense. Even if one thinks that at last, only the work of the geniuses counts, what is still debatable, he should agree that geniuses stem from the mass of workers, and that great discoveries rest on a great number of easy examples. Archimedes or Gauss grew up in societies were the average maths culture was very high. The same happens in sport: there has been Pele, because virtually every kid in every village of Brazil plays soccer.

There is no scientific society with isolated geniuses: it's a myth usually spread by those governments who want to cut research funding. As I see it, if one is able to do a honest cultural work, and to enjoy it, should do it with no hesitation. It has a great civil value, in a word were a lot of people instead dedicate themselves to drug trade, finance, politics, pornography, war.