But I thought the mods picked the name "Yuletide" specifically, and explicitly, as a gesture away from a Christian-o-centric conception of the exchange ...

well, if they did that, why'd they use a Christmas carol lyric as the name? The url is "yuletidetreasure.org" and the header on the main page is "While we tell of Yuletide treasure". I'm not saying they did anything wrong, mind -- I'm just saying that *if* they intended to introduce distance from Christmas, maybe going with carol lyrics was not the most effective way to do it. (And it's kind of a big "if", isn't it?)