Starting a new relationship and "meeting the parents" can be a panic-inducing event of being on your best behavior, remembering not to curse, putting your napkin on your lap and not mentioning that you met their son when he was blacked out at last call in a dive bar.
If your family has some traditions for gatherings that aren't exactly "normal," warning your new partner that nobody eats until your grandfather takes his first bite will help avoid any potential awkwardness for everyone. It's not fair to expect someone who hasn't spent their entire lives enduring your aunt's ten minute pre-Thanksgiving speech (with costume changes) to know instinctively to applaud at the end.
Still, going to someone else's house for dinner and helping yourself to a week's worth of food in one sitting while everyone else is milking their first serving isn't exactly reading the room. So, when a conflicted man decided to consult the online courtroom of moral philosophy otherwise known as Reddit's "Am I the As*hole" about whether or not he was wrong to ask his girlfriend to cut back on her portion sizes at family dinners, people were quick to help deem a verdict.