Further, the simple act of commenting on something in present-day is in no way "acting like it wasn't present" in the heyday of the commentator.

Also, it's not like they're drinking a glass of water. They're eating laundry detergent as a "challenge". It's extremely out if the ordinary, dangerous, and thus notable. Hence an incredulous response from adults.

The only person in the room "acting" like anything is you, as though what you said made a lick of sense in a vain effort to the the "above it all" guy in the room.