And selling a game to the general public is entirely different than targeting an individual and tempting him.
Remember, morality is not limited to legality. It can be both more lenient and more strict.
In the earlier analogy, the bartender saw the troubling behavior. Game design is not just analogous to how the drinks are mixed, but also the behavior of the bartender. If one is programming the bartender-AI and one can, but doesn't, include the ability to be watchful in that way, and the reason one makes that omission is to increase drink sales... well, that seems pretty morally wrong to me.
You don't see how choosing to only include in a game's design the things that undermine user intentions of self-control and never any of the things that support those intentions, how that is a moral issue of game design?
Games can perhaps be used to help teach or reinforce the helpful skill of self-control and other better angels of our minds. So possibilities of moral good are also clear. Instead, are you saying moral metrics don't apply at all? That there are no moral issues with how one designs games which treat their players little different from saps at a carnival? No moral issues with making games that better and better undermine the player's will and take advantage of systematic mistakes in the way that player's discriminate, while having regard only for the metric of sales and no other effects. Using someone else's weakness for gain is a moral issue.
Is it, or is it not, morally OK to tempt and socially pressure an alcoholic to drink? To construct a situation that contains many or all of their personal triggers and then offer and encourage them?
What about a table with some green food, some orange poison, and a sign explaining the color code? Fine for many, but as the doorkeeper to this banquet hall, how bad a case of red-green colorblindness need a hungry person express to you that they have, before it is morally bad of you to let them in to eat without supervision or aid in the discrimination?