A) It ignores entirely the modern day usage of the Santa hat (it is not really a religious symbol, it is more like a general holiday symbol)

B) Even if it were, say, a menorah, it could mean that the developers are Jewish. Why would someone of a different religion celebrating the holidays offend you? That would imply to me that you're intolerant of other religions.

C) It was obviously not placed there with bad intentions. It is clearly intended to be festive and fun.

D) It is a waste of developer resources to remove something they just added in.

E) It devalues issues that people with genuine offenses might raise in the future, i.e. the boy who cried wolf.