That the stock market is a zero sum game, If you take out the value creation by the companies,  is very well understood.

How to separate out investor and speculator is an interesting question, but seems to defy clear-cut delineation. One way to look at it is perhaps: if you are mostly focusing on the value creation, you are an investor; if you are mostly focusing on the "zero sum" part, then you are more likely a speculator.

Poker is certainly fun and useful for exercising brain, but to say "德州扑克是价值投资者的一项必修技" is certainly stretching the logic.  In any event, I think it is a good idea to start a poker club in parallel to the investment club :-)