Because at the moment, it was the culmination of an admission that they couldn't take it anymore, especially when they were losing frequently and their bankroll wasted or completely gone. Of course, losses are common in gambling, and it's important to understand that this is a normal part of the game, and it's extremely difficult for every player to endure frequent losses. But then the pain subsides, money comes in from work, and after a few weeks or months, the player thinks, "Why don't I try to win it back?" and then gets back into the game. This can happen dozens of times until the player loses too much and stops. Although it's worth noting that sometimes players can also win the jackpot, these are, of course, rare and lucky.
Of course you're correct to a great extent, but if these gamblers haven't found the conviction to gamble responsibly and with a budget, they should not return because it would be the same old story again. Coming back is natural since gambling is magnetic in nature, but returning without reshaping your gambling habits after such a big loss that saw you give up is not advisable because sooner you may likely get into a bigger financial mess.