Should a state be liable for selling lotto tickets to a gambling addict? Make an argument that it should not be.
Court cases have bartenders liable for serving alcohol to someone who is already drunk Gambling is an addiction too
To make this argument, say that the state should not be liable for this because there is no way to determine who is a gambling addict. This is a very different situation from the one that you mention involving bartenders and drunk customers.
In the bartender scenario, the bartender is not being asked to determine who is an alcoholic and who is not. He or she is being asked to determine who is drunk at this moment. That is a very different thing.
There is no way to determine by looking at a person if they are a problem gambler. For a gambler, there is no visible analogy to a person who is drunk. A person selling a lottery ticket could not look at the person and say "you've had too many, I'm cutting you off." There is no way to know if the person has bought too many lottery tickets.
Liability only exists when an actor should have known better than to do something. There is no way that a lottery ticket seller could typically know better than to sell someone a lottery ticket.