You can make the point that social media has real positive benefits as well as negatives without minimizing the well proven fact that gambling creates a form of addiction in a significant proportion, though not all, of its users, one every bit as devastating as heroin or alcohol.
Seems like you're overestimating how many people are addicted to gambling. Much in the same way those who are anti-alcohol will conflate responsible drinking with alcoholism. Gambling can be just as terrible, but it is different than heroin and alcoholism since it does not have a chemically addictive component. Reducing all addictions to being the same thing is damaging to addicts and addiction recovery. Much the same way reducing all crime to the same thing is for inmates of the prison system. You're removing nuance and difference which helps promote understanding.