That is a problem that I don't see the point of, if a person has an expired document it is not possible that they will not allow that document, what they have to verify is that it is the person, that that is their identification. , then they should value it, that's the same thing. What happens with the passport, the fact that it is expired does not mean that the person changes their name or becomes someone else, that cannot be, that is something that does not make any sense, because I do not see any sense in it, that is why I insist In this, they should be worth it, it is identifying the identity, everything else is fine, and it is not just the casinos, it is any site including the exchanges...
You have a point, but platform asking IDs is more than that just accepting client's IDs. Anyone can make fake ones, change their birthdate and anything in the ID when casinos are very strict to age, they can even impersonate others. If these platforms accepts expired IDs their AML policy is useless, of course there's little to no way they can verify if the ID used is legit since what you need to do it to make picture of it so the cons are many when accepting expired ones.
You see, most of casino or online platforms just comply policy of KYC, it's for AML mandate of the authority, as long the ID is clear, not expired and if a person is in legal age youre good.