Incorrect. And I think it's more accurate to say "it's silly and annoying for me" as no one else appears to have a problem or are self-aware enough to keep their personal feelings to themselves and let the person in question enjoy a little fanfare.
The people who need to know, already know. It's not because it's a secret cabal and honestly, I should have kept my mouth shut but I'm tremendously happy for him and he needs to know, in the words of the President (then VP): "This is a big effing deal".
Here's the "behind baseball":
While I'm celebrating him getting hired, I have zero idea if someone else on the forum helped him get to where he currently is. So the "welcome to MY" team may be misinterpreted to the person that may have helped him as "My Tribe > Your Tribe" and it's not accurate nor do I want that because we need people across the spectra helping one another achieve their career ambitions and I run the risk of alienating A LOT of people.
Now he's an adult and a professional who has an appreciation for the shout-out, but also an appreciation for discretion so he can make sure his situation is clean and tidy in his professional circles and has the chance to be sure there is no animosity with his colleagues and anyone who helped him.
A personal story, I went to bat for a person a few years ago pretty hard, got them in front of the right people, shook the right hands, lobbied hard to get them scheduled for an interview and they got the job. Indoc went well, training went well, IOE started and then I straight-up got "ghosted" for about six months after IOE. Then on social media I found out that they had just finished indoc at another airline and didn't think it was important to say "I took another opportunity" or even acknowledge the efforts I went through to make sure they had an opportunity at my airline.
Congratulations are in order for our friend, but if I'm not careful with it, it may be a slap in the face of someone else who helped him. Anonymity provides that ability for him to steer any potential conversations he needs to have with timing that he decides.