It is 'outdated' as understanding that this is how D&D generally is played. This doesn't imply that no one plays that way or one couldn't talk about that sort of play.This doesn't make any sense. There are people on this board that push Classic approach concepts. Look at @iserith, for instance. He puts forth a clear approach to play that is very much aligned to Classic approaches within 5e. The idea of how B/X plays isn't "outdated" in discussion of 5e play because it very much can be emulated quite easily. That it's not the most common approach today is of little to no import to the discussion. You are trying to gatekeep discussion of B/X play because it's outdated and doesn't reference current edition but those references are to the approach to play, which is still valid. It's more clear in B/X play, hence it's use as an exemplar.
What really fun here is that you're outright admitting that discussion must genuflect to current edition or be considered "outdated."