SonOfGroucho: I'd like to shove tolerance down people's throats :-) An atheist with a Christian upbringing, I say "Happy Christmas" myself (though, if I remember, I'll say happy yule to my pagan friends, and I make sure to put happy new year as well as merii kurisumasu when I send cards to my Japanese friends), and don't personally find Merry Christmas offensive. But I do take offence and people who take offence at "happy holidays" (this doesn't include you, as you were asking, not claiming offence).
John: Yes please! I fail at diy christmas, despite always having great intentions. I've sent no cards, never mind handmade ones (though I did make a couple I haven't sent!) and I've only made one present, which isn't quite finished yet...
SonofGroucho, you may not be religious at all, but were you brought up with a nominally Christian background? You might feel differently if you had a different religious upbringing, or beliefs now, especially one that also has a holiday at this time. Holiday season really is broader - it's not just that Christmas has become secular and can be enjoyed non-religiously; there are a number of religious and cultural holidays at this time of year.
"You can't swing a cat without hitting some kind of demonic activity. Not that I swing cats. Or eat-- nope. Cutting way back. Cholesterol-- morals. I mean morals" - Clem, Buffy the Vampire Slayer, Season 7