>if an author decides to write on a topic, by definition they believe the topic is worthy of consideration.

This was not my point; rather, it would be possible for a philosopher to argue that they are not worthy of moral consideration, or not worthy in some way (but are worthy in others) - "worthy of moral consideration" refers to the object having moral properties, or that an activity is morally relevant. It does not mean that the topic isn't worth arguing about. For instance, some moral philosophers have argued that animals are not worthy of moral consideration.

>is the default and widely accepted one, with hardly any credible objections.

I don't think so. Consequentialist accounts of the morality of violent video games and even other media more generally cite arguments such as increasing aggression or anti-social behaviour. I'm not convinced the data is correct, but I think that among the general populace, some topics and actions are mff-limits morally blameworthy, such as engaging in a simulation in which it is your choice to molest children.

>This is a distinction without a difference.

It very much does make a difference, at the very least in the way we talk about morality. "It's against my ethical code" is not the reason you'd hear when you ask why someone disapproves of torture. "It's immoral" is what you'd hear, and it means something much stronger, something we act on in the world to the extent of restricting others, and the reason we have the state, courts, justice, the non-aggression principle, socialism, libertarianism, capitalism, and any other ideology or justice.

>Morality in the sense that "all rational people should accept it" is basically an empty set

The fact that no metaethical theory makes the case for you sufficiently does not mean that none of them do, and the same "choose your axioms" argument could me made just as well against, say, mathematics, identifying colours, epistemic standards, or logic itself. The only token that allows you to throw out the grounding of morality allows you to throw out anything else too. That's not to say moral facts necessarily exist, but many people take them to insofar as they provide for (almost) uncontroversial moral facts involving, say, slavery or torture.

There are very good arguments against morality in general, but "you can't prove any particular code of ethics is the right one a priori" is not one of them - the sophist's hammer is too blunt to be useful to me, you, or anyone else.

>This is a moral intuition, there is no way I can rationally convince you in a non-circular way that you should absolutely accept this fact. If you don't, the discussion is kind of over.

There is, assuming that we share systems with roughly the same results, just as you can convince me that A == A assuming we share similar logical systems, or that the earth is round assuming we seare similar epistemologies. They don't even have to be the same in order to rationally convince someone of internal consistency, which is what matters here.

>Again, it's a moral intuition without any absolute justification.

We could continue reducing the question down to a single basic statement of any ethical theory. That's not a problem, because although we may say on forums that morality is relative or descriptive/non-normative, we act as though it is objective and absolute, and we frequently ground our rational actions in that belief.

I'm sorry to say I don't think I'll do a good enough job of explaining or relaying the arguments against the immorality of video games more succintly than they have been made already, but here are PDF links to a good non-paywalled paper: https://scholar.google.com/scholar?cluster=18384555564403984...

The papers citing this one also do a good job of arguing that some video games can be immoral to play, but none are as high-level and cover as many ethical bases as this one. It's worth noting that even this author cannot say that video games are unworthy of moral consideration. "It's just a game" is by no means his approach here.

Edit: here is one such paper I cited in my other comment that argues the immorglity of certain multiplayer video games from a Kantian perspective: https://link.springer.com/article/10.1007/s10676-019-09498-y