Because some people may choose to keep chasing that loss and keep losing till they endup having nothing left to lose , so better stick with taken a break first and find what will help to clear your mind first before going into another sector of gambling.
You're right. It is better to take a break when we feel it is getting harder for us. If we chase the losses, it is even the way to lose more money. Spend more money will never increase the chance to win in gambling. It is because win in gambling is mostly based on luck. Even if we force ourselves to gamble with more money, it won't work if we don't have luck. So it will just be in vain!
Taking a break will not easy for those who often playing gambling because they want to recover their losses and wins their money back. But they must keep trying to take a break for a while to reduces our emotion especially if we already lose too much money.
That is why we must have allocation for playing gambling and stick to our rules while we don't use all of that allocation money just to playing gambling for that day. We must remember that it is enough to playing gambling with that money and it is better if we can keep some money in our account that we can use to playing gambling in the other days.