It's a greeting.
You want to say Merry Christmas?
But don't insist on the latter when anyone else who tells you the former.
As much as many of rail against it, this smacks of POLITICAL CORRECTNESS.
It's a big wide wonderful world out there with all kinds of people wanting to celebrate just like you do, maybe not in the same manner but for the same basic reason.
So let's drop all the pretense.
Someone is wishing you well when they say those words.
You should be grateful and if you're willing, wish them the same.
Now, and especially now, after the year we've all had, we can come together in spirit and give each other the thing we need most in this life...
Sorry. Didn't mean to yell.
And Happy Holidays.