Years ago, I worked in a job where there were recurring tasks that needed to be performed every day of the year, holidays included. During the time I was with this organization, I worked on Thanksgiving and another guy worked on Christmas.
The point being just that, yeah, there are some jobs that need people present all the time. Sad but true. If you feel you are being singled out in some unjust way, discussing it with management or HR or whomever seems appropriate. If you just somehow got picked at random, it would be reasonable to ask to switch -- maybe you can volunteer for the next holiday -- but a lot of people expect Christmas off, regardless of personal beliefs, so there might not be anyone willing to trade. :-)
