Whatever the reasons were (and we can probably guess some of those), they probably spent significant effort to picture it in the most palatable way possible.
My take would be:
* They hired a lot of people in a short time and with this probably their productivity fell a lot. They want to remove ballast and hopefully improve average productivity.
* They are scared about falling share price. A lot of Meta employees get significant part of their comp in form of shares and so falling share price will mean their best people are going to start to leave or they will have to increase their comp considerably. So they are looking to appease investors by cutting costs.
* They are loosing users and expect to start loosing ad revenue. Having on idea how to improve their revenue the only way out to stay in the game for longer is to start cutting costs more aggresively.
* They have no idea what to do with all those people they have hired because their CEO is doing something else at the moment. And (in my experience, not based on facts) the culture at Meta is very likely that everybody is looking up to CEO or nothing happens.
I'm sure this, LLAMA and the other projects that they have will help drive up new creations, companies and progress.
I'm also sure that this kind of openly sharing code and research will drive up business value for them. It may be hard to say right now what it is, but I'm sure it will.
That's the difference of a founder-led company vs. market led. Google is mostly concerned on short-term goals so they don't report a single bad quarter or has too high CAPEX on a project without profit on its sight (like VR).
Once Meta finds the killer app for VR, all the other companies will be so many years behind that they will need to buy software from Meta or not take any market share in this new space. Similar to what happened about AI chips and Nvidia. Nobody was investing enough on it.