Slot games are very addictive, you can suddenly get big wins, but one thing to note is that when you win a game, you will not get a second win until you lose the money from that win. They are arranged in this way, so if you do not keep your mind set right and cash out at the right time, you will not have any money left over at the last minute. However, casino sites sometimes give very big jackpots and some lucky person gets it randomly. If that lucky person is you, then you can win something big. Otherwise, it is better to cash out with small profits. However, once you start playing the game, it is very difficult to keep your mind set stable.
If you win, let's react responsible and knowledgeable as well as experienced in order to secure your win and your initial gambling fund. Not all gamblers are able to do this, hence even they merely win big, they can not protect that won money and almost very quickly after that they lose that money entirely.
They possibly already read information and advice like shown in your post or anywhere else or they did not read it any time, but it's not responsibility of casinos to do that. It's their money and if they have actual concern about how to protect their gambling fund as well as clearly have thinking of how to defend won money in order to use it for partially or entirely change their life quality much better, they must do proper research on risks and what to do safely.