I have to admit, as a secular humanist who rather likes certain parts of Christmas, I felt a little insulted. If Jesus is the only reason for Christmas, then why bother with family gatherings? With spending time cooking a special meal to serve to your loved ones? Why bother exchanging gifts? Why bother doing anything except going to fucking church??
In Christmas, I find meaning in love, caring, friends, family, and togetherness. I find meaning in generosity from those who can afford to be generous. I enjoy being with people I like, and love, and feel close to, and having it be a time when people try to get together with those they love, but aren't normally able to see. Goodwill towards men, peace on earth: these may be cliche, but they have meaning and importance.
I don't know about you, but those seem to me to be damn good reasons for Christmas, even if you're not a Christian.