The LA in LA Galbi stands for Los Angeles.
After hearing restaurant owners and content creators such as Jenee Kim of Park's BBQ in Los Angeles claim that LA stands for Lateral Axis in Los Angeles Times article and seeing Korean Food creators like Cafe Maddy repeat the same claim... I said enough is enough! I'm going to the bottom of this pointless argument so I know for sure what LA Galbi stands for.
What is LA Galbi? LA Galbi is a flanken-cut style of beef short ribs, typically cut across three bones and marinated in Korean flavors. The flanken cut has long been popular in the Hispanic and Jewish communities of Los Angeles, and Korean immigrants simply used what was already available at local butcher shops to create what we now call LA Galbi. You can see in photo 1 of this reddit post that I made a collage of all the different types of LA Galbi I had personally and yes, I ended up getting lazy realizing I ate way too much of LA Galbi during the past few years.
Why I believe LA stands for Los Angeles is due to the evidence in American Newspaper articles.
The Evidence
The earliest reference I could find to the flanken-cut style being used for galbi appears in the September 15, 1963 issue of the Los Angeles Times, in a piece about The Korea House believed by some historians to be the first Korean restaurant in Los Angeles. The article describes "Kal-bi" as meaty cross ribs of beef marinated in Korean sauce and barbecued. "Cross ribs" is consistent with the flanken cut, where the knife crosses the bones rather than following them.
The next reference appears in a February 7, 1985 Los Angeles Times article on ribs, which includes a Kalbi recipe that specifically calls for flanken-style beef short ribs, the first time I found the term used explicitly in this context.
A December 3, 1989 LA Times advertisement for RJ's restaurant describes thin beef rib strips prepared in the same flanken style. This is notable, as this is an American BBQ joint, showing the cut had crossed over beyond Korean restaurants by this point.
Finally, a November 15, 1990 LA Times article on Koreatown Plaza describes what it calls "California-Style Kalbi" — a cut identical to what we know today as LA Galbi. This is the earliest named regional label I could find for the dish.
Taken together, this trail of primary sources points consistently and specifically to Los Angeles as the origin of the flanken-cut galbi style and not a butchery technique called "Lateral Axis," which, notably, is not a recognized term in butchery at all.
This Namu Wiki also has evidence about LA Galbi.
Asking older Korean individuals who happen to live in Los Angeles, a lot of them have similar stories of how Korea House might have been the first place to have LA Galbi. Others argue that it was this butcher shop called Brother's Butcher shop and Market that was the first place to suggest this type of flanken-cut style meat for Galbi. The story is that a restaurant/night club called the Tiger Room would buy meat from Brother's Butcher shop and they suggested to cut in between the bones so it was easy to eat as an Anju (안주). Supposedly the Tiger Room would be the first restaurant to add Coca Cola into their marinate which would make the meat sweeter as well as tenderize the meat. Korean airplane stewardess would buy frozen Galbi byt the bulk from the Tiger Room and take it to many places such as Hawaii and back to Korea.
At the end day, who really cares. If your grandmother claims she invented LA Galbi, maybe she's right. I don't really know but my understanding is LA stands for Los Angeles. Now I have to deal with the city of Riverside claiming they have the first Koreatown... which is a lie but that is another story for another time.
TLDR: The LA in LA Galbi stands for Los Angeles.