When I was a christian, I used to hear people at church complain about it every year. I can't remember any of them throwing a fit in public about it, though, so it might not have been obvious from the outside.
Well actually, plenty of Christians I knew complained about it on facebook and other social media, which could probably be considered "in public." You get the point tho lol.
It started a while back when companies stopped saying Merry Christmas and started saying happy holidays so they could be non-denominational. Christians took it as a personal offense, but it's just companies trying to make money off of non Christians during the holidays. No one individual person actually gives a fuck if someone says Merry Christmas.