Adult refreshments

I don’t think it’s a moral issue. It’s a convention, perhaps based on the fact that they have life experience and it’s worth giving them respectful treatment because then they’ll be listened to more and not belittled. Sometimes we’re required to respect them in action because it’s harder for them (for example, standing up in front of them on the bus). Although now that there’s such an expectation, even if it’s not entirely justified, perhaps deviating from it is inappropriate.