wow, what a dick.
I'm not religious but I would never reject a celebration that brings gifts and chocolates with it... and generally improves peoples otherwise grumpy mood (except for a few individuals like this one).
I used to put up a christmas tree and lighting, and exchange cards when I was a kid, but not for a second did I give a damn about the historical/religious context of the event.
People will be celebrating most of the events we have now, even in 100 years time when significantly fewer people will be religious.