People don't need to, religious or not. I had a friend in school that didn't celebrate it because he didn't believe it should be a celebration so much as a strict religious affair. But, everyone should be perfectly okay with the spirit of giving, and of course, the simple acknowledgment of another religion.
It is acceptable for non-Christians to celebrate Christmas. The holiday is more of a commercial celebration than a religious festival. All people should be welcome to celebrate the holiday in their own way. The original intention of the religious holiday is to be generous and friendly to your fellow man.
Yes, non-Christians should celebrate Christmas if they want too. Non-Christians shouldn't be forced to celebrate Christmas of course but if they choose to celebrate they should be allowed to and nobody should have a problem with it. Christmas is about kids and most kids are not as deep into religion as adults anyway.
If non-Christians want to celebrate Christmas, they should do so, and if not, they should not. Nobody should be forced to celebrate any holiday, in a religious way, but Christmas is also part of the culture of the Western world. I'm not Christian, for instance, but hung Christmas lights at home.
Non-Christians should celebrate Christmas. Anyone that wants to celebrate the holiday should do so if they want to. Some religions celebrate the Holiday in many different ways and will continue to do so. I think that Christmas should in one form or another be celebrated with family and friends for generations to come.
Christmas is a holiday that much of the world has shared for many years. It is considered by many to be the best holiday of the year. It would be very harmful to society if only Christians were to celebrate it. Non-Christians should be allowed to celebrate Christmas if they want to.