Define "drugs". Alcohol is a drug. Most users aren't addicts. So is tobacco. Most users are addicts. Cannabis? More like alcohol than tobacco in terms of addictiveness.
There may be some selection bias. Smoking tobacco is an unpleasant sensation. There's no reason to do it other than the addiction and the effects on your brain chemistry afterwards. Whereas many alcoholic drinks taste great in their own right and would be consumed even if they had no chemical effects.
I suspect gambling is like alcohol or cannabis. Engaging in it affects brain chemistry. For some people that's addictive. Most people are able to enjoy the activity without being hooked.