What makes you say that humans are very bad at gambling?
Throughout our evolution, we as a species have had to make several extremely risky gambles that have paid off, I wouldn't say that we're bad at gambling.
We had to risk crossing the oceans to find new lands, we had to risk overthrowing and electing certain leaders and we've had to wage wars we might not have won.
We're definitely not bad at gambling.
I agree, we are not that bad at gambling, I think the things that make it bad is when the gambler got addicted and dont know how to control himself at the game and that they forgot about the plan.
Being too emotional leads the gamblers to lose more, as they keep following emotions from game after game that they've played, if you can hold your
emotions and deal with this activity with good form and right attitude you'll not going to find yourself being too much addicted it will not ruin your life and you can easily go and move forward every time you deal with this activities whatever the results.