YTA, but i kinda see where you're coming from. However Christmas is a family celebration and you're excluding her from it. Would you do the same if she'd come out as atheist or agnostic?

As an atheist myself I celebrate the holiday as a way to maintain connections with friends and family (also because i suck at remembering birthdays!). (In case anyone interested I have a Dr Who TARDIS on my tree and various geeky baubles and as much tinsel as i can stuff on to it!).

People of other religions in the UK are known to celebrate Christmas in their own way by participating with their community at large.

It stings as favouritism. Where is live thy neighbor?