For starters, you can only trade for 6 or 8 hours a day, so recruiting and training traders is a way to increase your income during non trading time. Second, who wouldn't want another income source(I don't think there is anything wrong with it either!)? Finally, while I agree that trading is not for everyone, getting some quality education is a good investment. One needs to learn strategy, software, mechanics of execution, how to handle news, RS, what moves stocks, sectors, etc. Most of that information is not available in books out there.
As for Mike Kestler, he is a good guy, and from what I've heard, a good trader....trading is a small community and word get's around.