After a carefully thinking about the topic and the reality of gambling, I want to agree with you partly because that statement is true but with some exception. A lot of people do lose in gambling but not everyone is losing so we can say that gambling is designed to give the house edge so they remain in profits. Part of the money lost by majority of the people will be used to pay those that would win and the difference being the profit the casinos will make. This is how I think gambling is designed.
Yes not everyone is losing but not everyone is winning. There is no guarantee that you in particular will win. That is why it is a gamble. You are still paying for the hope and the chance that it will be you. But doing this will definitely make you lose money. So some people just pay for the love of the game. They just want to be entertained and they do not think much about winning. If they win, then it is a good thing but if not then it is also not a big deal. Which is ideal if you want to keep your sanity.