Definitely, gambling addiction is a disease, it is kind of sickness, we should avoid it, to protect our bank accounts, family.
Gambling itself is not a sickness but getting addicted into it is considered as a sickness since its hard to control and stay away from it specially you are almost playing everyday and trying to cope up all of your losses. This condition needs a help from a psychiatrist if you are severely get addicted into it.
You are right, gambling itself is not a sickness, I am wrong. Because some countires allow gambling, especially developed countires, so should be legit, not a sickness unless addiction.