Many people are upset about this, but it is in my opinion an excellent thing. Mozilla and Facebook are working together to improve one aspect of Facebook's privacy
It's not like Mozilla is shilling and getting paid off, as some people seem to think.
This is how privacy is really improved, by working with the companies and governments that have power in the space, not by sitting in your cave using only librewolf and tor, and refusing to use anything you don't build from source and self host.
That only helps you at best, and the privacy abusers (google, facebook) will just ignore you.