I don't really see how Larry was being punished. Aunt doesn't want to host everyone under the sun, because she's old, she's tired, and oh yeah it's her house and she doesn't want too. Aunt counts Larry's new girlfriend as not family. Because the relationship is new. Prior to Thanksgiving they hadn't moved in yet, and post-Christmas they had. Ok, that's about a month, the relationship changed in a month's time, good for them. I've known people to start living together a week after they started dating. Everyone's time lines are different. But at Thanksgiving, they weren't living together. Maybe they were talking about it, maybe they were planning on it, but as far I can see, Larry didn't tell his Aunt this.
If Larry had sat Aunt down and said "Listen, Aunt, I know I haven't been with Jane for a long time, but we're pretty serious about each other, we're even planning on moving in with each other within the next month, I'd really love to have her at Thanksgiving to meet the family", Aunt still had the right to say no in that circumstance, but I think a lot less feather ruffling would have happened. And at least his family would've understood his stance. I'd have a lot more sympathy for him at least, if he'd acted like a grown up.
To me, he acted like a teenager at best. He wants his way. He will stamp his feet and hold his breath until he gets his way. And when they won't give in, he'll just do what he wants anyways.
Should Aunt have chewed him out in front of everyone? No. But that doesn't make Larry right either. I'm assuming Aunt was blindsided and understandably upset (I would've been), but no causing a scene won't fix anything. I know, my family loves causing scenes and it's yet to fix a single thing. If Aunt had closed the door and chewed Larry out, well, I wouldn't really have a problem with that. I'd probably do it. Then walk out, insist girlfriend sit by me, and act like she was the most fascinating person to every cross my threshold so that when Larry grumbled about getting chewed out on the way home girlfriend could say "What are you talking about, your aunt was fantastic!", but I can just be downright evil.
This Christmas my best friend's mother requested he attend the Christmas gathering alone. See his religious brother and SIL were in town. And well, best friend's finance is boy and so is best friend. And well...they love Best Friend of course, but it's just a bit awkward and golly son it'd make Christmas so much better if we could just pretend you're straight and single. BTW, fiance, 3 year relationship, living together, so committed. Fiance told him to go to his family on Christmas, he'd come with us to my grandparents, he understood, he loves Best Friend, and while he felt hurt by his future MIL, he wasn't going to ruffle feathers. Best Friend went, was peaceful and made his excuses to leave early in the evening and joined up with us.
I was hurt my Best Friend's mom. And it wasn't even directed at me or involving me. But that is an example of a family punishing another member for their life choices. When they deny girlfriend access to the next family function (now they live together and are seen as a social unit), or when they refuse to attend the wedding, then we can talk about punishing Larry. Until then, Larry wanted his way come hell or high water, and he was just going to do what he wanted no matter the consequence.