So having "Good manners" is all about putting up with other people's bullshit religions and holidays with a smiling happy face? Screw that! Now go have a happy winter solstice, because Christ wasn't born in the winter (if he even existed).
Actually, really good manners is to try and not to force you views on strangers. Your view is that, since Christians are the majority in this country, that we non-christians should just suck it up and put on a happy (non-bitching) face. So you just don't care about people who aren't Christians, they can just shutup about it already as far as you are concerned. You do know that the Christian religion isn't the largest organized religion on the planet?