Hello Dosho,
Since I, too, brought it up, I should offer my explanation. Birthday threads are nice. But they could be problematic.
First of all - what about those people who doesn't get a happy birtday thread? I'm sure it can bring out feelings of being rejected, overseen, or simply ignored. Who gets a birthday thread? The most popular? People we tend to notice? People we see accidentally on Treeleaf's "today's birthday is ..."?
Second of all - and this is purely a forum aspect: many threads on literally the same subject tend to clog up a forum. This is, after all, a discussion forum as well, and sometimes a lot of threads on the same subject is making it a bit heavy when you're sifting through the latest posts, to actually find discussions or unique subjects that hasn't been delt with a hundred times before.
Forum-wise, I think it would be good either with monthly celebration, or a "birthday thread", where all these compassionate posts could be placed. That doesn't solve everything, but at least it frees up some space, and makes it easier to find subjects and navigate on the board.
Or maybe I'm just grumpy because I don't celebrate my birthdays anymore.
For what it's worth.