It’s Facebook’s business, literally.
No one is forced to work there.
If they have to pay more to hold onto talent in the more expensive states that’s their business.
I’ve heard for years, just anecdotal evidence but have heard often, that companies in the big cities in California have a hard time recruiting people from other parts of the country, because of the higher cost of housing, and living costs in general.
I’ve heard, again, just anecdotal evidence, that some people don’t want to live in some California cities, even at a higher pay level, due to quality of life as well.