If you didn't notice you will never see Merry Christmas as an event...just as you did not see Halloween as an event. There might be some events that fall inline with said holiday but they try to be sensitive.

To your point 4 if that were the case certain groups should totally be offended by Halloween event. And...ooh this game uses magic...it's...you know where I'm going with this. Let's just end it there. It's A GAME!

And the forums do have SPECIFIC rules...which I bet most have never read. It's very specific...as to what's allowed.