Suppose you saw a piece of candy lying in the gutter. Would you pick up that candy and eat it? Of course not! That candy is unclean. Like that candy, holidays may seem sweet, but they have been picked up from unclean places. —
So by using the WTS's particular brand of brain-dead logic, that would mean that their own religion is something "unclean". They admit (when pushed into a corner) that they used to celebrate 'pagan' holidays, brothers were allowed to fight during WWI and up until 1945 (I think) were allowed to take a blood transfusion if they saw fit. They used the Cross, the founder of the religion was a strong believer in Pyramidology and the have a laundry list of false date settings.
Naturally, the R&F won't see the obvious analogy here. They'll all sit there with glazed looks on their faces as they condemn all other religions in the world except their own as being "unclean".