I am guessing the "we know what's best for us" crowd is very young, likely with young children or no children at all, and from families that haven't been harmed by family members who are addicts.
Addiction is NOT a victimless crime, and the family members of addicts are held hostage. Gambling, drinking, smoking, weed, and drug use have all been banned for this reason at one time or another for this reason, and not by "moral due goodness trying to limit personal liberty".
People with families and responsibilities vote, and things that tend to destroy families and ruin lives get pushed away. We have conceded alcohol, but there are MANY people whose lives have been negatively impacted by alcoholic parents or children who would be willing to ban it, not on moral principle but to drive it away from their life.
The moral social net to support those who will be gambling, but cannot afford it, and their families, better be factored into all of the perceived benefits. Gambling addictIon is real and highly destructive.