We know that alcohol has a negative effect, whether we play gambling or not. We can lose control when we drink alcohol, and if we play gambling, that can make us get serious trouble, which is we can lose the money. I already saw a person who is drinking alcohol, and that makes him say anything even shout to other people. I cannot imagine if that person drinks alcohol, and he plays gambling at the same time. Maybe he will make other people become angry with him and want to kick him.
All of this is true. But then, we don't have the right to dictate terms on anyone else. We expect people to behave responsibly. While consuming alcohol, it is the duty of that particular individual to make sure that he doesn't consume too much. Similarly, while engaging in gambling, it is the duty of the gambler to make sure that he doesn't get carried away. He needs to stop it, when it becomes necessary.
You are right that everyone is responsible for his own acts but there are mediation and counselors who teach and help people take the right decision. If any person is getting addicted to gambling or spending more time on gambling, his friends and family should know this and should talk with him so that he is not lost in all this.