I just think that celebratory thread are good and so far such thread are allowed because they don't break the rules [if not too much] with free speech considerations in mind.
While these self-congratulatory threads maybe even had honest intentions at the beginning to sort of inspire new members that is not impossible to rank up after merit system introduction, over the years it mutated into merit-fishing ego trip. Everyone is still free to create those, as others are free to ridicule those that create one for every minuscule feat they achieve here.
Monkey see, monkey do. He is only doing this because he saw others showering similar threads with merit, so imho they as equally to blame as that those are actually opening them.
And if we do not respond to those topics, let alone send merits, this tradition will end.
We have an interesting situation that people here are rarely willing to call a spade a spade and instead just go with the flow and keep repeating what others are saying or doing. I've been on various forums for many years and never saw so many people patting each other on the back, unwilling to say what they really think and eventually creating herd mentality.
Anyway, good initiative, I hope it picks up.