These are all fairly strongly regulated. Did you choose bad examples on purpose?
So like,what about making gambling work like credit cards: you get a license that allocates a monthly cap based on a combination of credit score and income. It starts very low and scales up to, I don't know, 10% of income?
We should be free to ruin ourselves if we so wish, but if we are set on a track like that, others should be made aware so they can react as they wish.
Same with drugs, if you get a drug use license, then employers can deny you jobs, you may not be allowed to drive, be trusted with loans,etc..
You get rights, but they come with responsibilities and restrictions.