Yes, you are right,no gamblers bet to lose money. They do it in the hope that they will win, but sometimes they are not right and face losses. However, those losses are not negligible, they are very small, and they can affect someone's balance. But when they combine, they really make an effect as a whole. There is a famous quote, Learn from your mistakes, and you will succeed, and the losses are the cause of these mistakes. So if you can't consider your losses, how can you move forward?
I must say that not every gambler gambles for money and profits, and there are a lot of people who gamble for fun, and they have an allocated budget for their gambling activities and they barely flinch when they lose that amount because they've already decided that it's a budget that they're going to use on things they like doing, be it gambling, watching a movie, going out, etc. So, if you've ever been in that position yourself, you will understand that sometimes you have to do these things to keep yourself going in life; it's important.
Have you ever seen people spending so much money on video games? Mostly buying armour, dresses, and gun skins only to make their experience more fun and enjoyable. Why do they do it? It's because they like doing that, and they enjoy their game more when they do it, and they know what they're spending on it is an amount that they've put aside from their total income and they don't care what they are spending it on as long as they are having a good experience.
So, sometimes, you do things for fun, and you spend money on those things because you can afford to do it.