I understand your reasoning. But another way to look at it is diversification of income streams. There are weeks and month(s) where he's down over six figures. Multiple streams make total diversification sense.
Think of it as a business. GS has i-banking, M&A, wealth management, and prop trading(or at least used to before Volker Rule). Even as big as them, they can't just rely on the highly volatile prop trading only.
So, why not making $ and also have an educational biz on the side? There's a sucker born every minute who are knew to trading that he can sell infoware.
Totally legit business-minded thinking.
It’s legit if you understand the business rationale for diversifying.
Goldman does it because
1. Synergies
2. They hire people to do the work. (They can add time invested to the new business line)
In this guys case, the synergy is supposedly negative as he’s giving away his secrets. Unless he’s more profitable front running his clients (then there is synergy).
And his Time is limited and he has to chose where he spends his 168 hours/week. Is selling courses worth it if you are making 100k/week trading? Shouldn’t you spend you time maximizing your trading or if there is no marginal return spending your time trading then spending your extra time maximizing your return by investing your excess capital in things like real estate which can diversify your income without requiring significant amounts of your time. If he can hire someone to do his trading or to teach his course then the diversification through selling education might makes sense.

