Is it ok to send a Christmas card to an agnostic?

Chirstmas is a time of giving. It shouldn't matter what religion/non religion you are. Just don't pick one that talk's about "the birth of our savior" or how it's the time to praise the lord. Someone gave me a card like that (for all they knew, I could've been Muslim or Jewish, so either way it was kind of rude to assume I believed/ should believe the same as they did).

Christ wasn't even born on Christmas, so it seems that Christians shouldn't even be celebrating at this time.