I guess it's cultural, but I have observed many times that especially in America, there is a lot of emphasis on individualism - the cult of the person and their own achievements is placed above all else.

Even if the fix was done by one "dedicated employee" , they still belong to a team of people working together. I feel like singling out one person like this is almost rude to the rest of the team.

Do you mean that FB only has one single dedicated person looking at Whitehat tickets or that a single developer made the fix?

A single developer made the fix.

And in all likelihood, someone else monitored the incoming reports, recognized that this was a high-priority issue, and fast-tracked it to the developer. On top of that, I don't know Facebook's process that well, but releasing something that quickly probably involved some coordination to get it out so fast. Maybe someone else verified it, maybe someone fast-tracked it through the approval / launch process, etc.

Even things like bugfixes are rarely entirely creditable to only developers.

Judging by the name of the endpoint, it probably wasn't a super-complicated fix anyway - just disable / blacklist the endpoint that was obviously a mistake / test.

Who sometimes has a day off, or takes a vacation, or has an illness, so you’re looking at a minimum of 3 persons...

They have a dedicated Bug report team that sifts through the nonsense so it can't just be one person..