Gamblers have this feeling that they can win with the money that they borrowed therefore they will risk the money and end up losing the money. They repeat this process many times but still end with the same results. If you advise them to stop they will refuse because they have few games that they won but they would not know that they are losing more of the bets that they are taking than winning it. I think it would not be good to borrow money to people that are gamblers because we will be putting them into more trouble. I have not seen an addict that can hold someone money without using it for gambling or other irresponsible things like drug abuse or going to do fornication because they can not hold money but only to throw it away.
Gamblers feel that trying to guide them in the right direction is futile if they become addicted or cherish gambling as a money-making scheme. I have observed a gambler who lost so much by which he also lost human strength. When asked about quitting gambling, he says he can't find any other way to recover his lost money. He feels that it is difficult for him to recover the amount of money he has lost in any other way. He said he would recover the money he lost from gambling even if he borrowed. But he is reluctant to hear about what to do if he loses again. Of course he cannot deny the reality.
This means that one of the reasons why it is always difficult for a gambler to get out of addiction or stop gambling completely is that they have not been able to let go of everything that has been lost before, as you said, they say that they no longer have a way to return something that has been lost. and actually that is an idea that should not be expressed by a gambler, because from the start it has been clear that gambling is an activity of winning and losing, meaning that if you lose and lose money then that is normal.
Gambling is not a place to make money, meaning that no matter how hard you struggle to return something you have lost, it will always be a futile action, because in the end it is clear that you will most likely end up losing a larger amount of money.
As you said, the people you asked said that they would be able to get back the money they had lost in gambling, and I would say that in fact they were being played by their own hopes, and this is why we always recommend to anyone, especially beginners, to first assess gambling with a rational mindset and perspective, because by doing this it is definitely less likely for them to put their faith in the wrong place.