When gambling becomes an issue and a life problem then quitting gambling is not quitting your life its getting your life back! I personally cant understand how people let themselves get to that point where they loose everything for a game. Its supposed to be a fun activity not ruin life for it.
People lose everything for gambling because they become greedy, they want to have an easy money so they think that gambling can give them that or maybe others just want to gamble without them noticing that they become addicted already. There are a lot of reasons actually but it all boils down to money.