Why Complain or Take Offense?

It always bugs me this time of year when I hear about all the complaining about holiday greetings and whether it's PC to use them or not. Why does it matter? I know the arguments people use, but I just don't understand them. If someone is wishing you a happy or merry whatever, why get mad instead of feeling good? I've been wished a happy Hanukkah, happy Kwanzaa, Merry Christmas, & happy Holidays. I love all of them, even if I don't celebrate all of them. To me it doesn't matter. Most people celebrating any of these can feel the Spirit of the season, so their greetings and well wishes are meant well. I would love it if everyone celebrated for the same reason I do, but just because they don't doesn't mean I should criticize them or dismiss their traditions, just like I hope they'll let me celebrate for my reasons and not criticize me.