It's just so unrealistic. If I was the kid in that ad, my parents would've taken my phone away.
Not at all. I have a sister-in-law who always brought a book with her to the big--and I do mean BIG--Thanksgiving dinner. Everyone in the family knew that at some point she would have had enough of socializing and she'd hide away with the book. That was her, the introvert. No one ever forced her to participate in the socializing beyond her comfort level.
There are parents who "understand" that getting a certain kid to come to such an event is as good as they're going to manage. Getting him to participate by, say, taking away his book or phone, is only going to make him more resentful of the event, not grateful and part of it. So they don't take it away.
"Misunderstood," however, does show the boy helping out his sister, etc. He's not entirely disrespectful or rude. And we can't be sure that the "Misunderstood" label isn't us, the viewers, rather than everyone else in the video. Maybe they all know what he's doing with that phone and approve. Maybe they do understand him--and we are the ones who don't until the end.
Hence, I would say that it's not as unrealistic as you think it is. It's just "personally" unrealistic. Your family wouldn't stand for it, but I know families that would be fine with it. They'd assume that the kid was of an age where he needs to be in that shell, and that so long as he's there, helping out his sister, it's all good.
