Although he is aware of your "gambling" comment and he agrees with you.
Imo every trade is a gamble, even GS with super computers, super data, HFT, you name it.
Every trading session has losers - losing trades, not talking about loser people.
Losing is part of trading, if someone can't accept that gambling is exactly the same.
Another similarity is the addiction, trading gets you hooked. All smart experienced winning traders are hooked, addicted to trading, if they weren't they wouldn't be where they are. Trading involves huge commitment and attention.
Where many get hung up with 'gambling' and 'addiction' is the common perception of dropout people, alchoholics, druggies, casino crowd who have no edge, lotto players, slot machines.
Those people are brainless, but I wouldn't call dedicated traders brainless even though imo they are gamblers and addicted to the game.
Another thing, trading often brings self awareness and stretches the brain to think.