Yes, it means that gamblers must realize that gambling is not only about the chances of winning but also there is another part that can never be separated, namely the possibility of losing, and as we know that everyone does not like the name losing money, while losing in gambling is a very possible thing that can make them lose money. So there is no other way to avoid the possibility of losing a large amount than by only risking a small amount.
It's fair to say that gambling will always be an activity that doesn't have any certainties and guarantees regarding the outcome at the end of the session especially when it comes to winning, and that's why many of us always recommend only risking small amounts. The fact of the matter is that no matter how confident you are in your choice of decision at the end of the day, confidence is not something that can guarantee victory. This means as you said that anything can happen even if we are very sure of our choice, and the other thing is that betting a small amount will certainly make it easier for us to take responsibility for any results, especially defeat.
If gamblers can realizes that they will have two result when gambling, they will not trying to use much money because they can lose anytime. They will difficult to wins as in gambling, we can only have a bigger chance to lose and winning in gambling needs luck althouhgh we are confident with our picks. When we placing our bet, we don't have to feels confident because anything can happens in the field so we are just placing the bet and wait for the result in the ends of the game. We can only prevents the big lose in gambling so we must not risks too much money when playing gambling.
Even if gambling doesn't have uncertainties, people will still placing their bet and playing gambling without stops because they thinks that gambling can gives them much money. They will still trying to wins even with more money and don't thinks about how much their lose later. If they can be wise when playing gambling, they will not risks too much money just to chase the wins because they will thinks that their chance to wins will not too big. They will just use the money they can afford to playing gambling because they don't wants to gets big lose from gambling. They only wants to be responsible when playing gambling and that's why they will only use enough money to gambling.