I want to know who they lying piece of trash is who told the child they used that she couldn't say "Merry Christmas".
That lying piece of trash would be the NEA. Students were not allowed to say Merry Christmas in school as it was considered to be exclusive of people of other faiths. Also, many but not all, employers banned saying Merry Christmas at work for the same reason. And even when businesses would try to say Merry Christmas, they would say Merry Xmas instead. Obviously, what Xmas does is to remove Christ from Christmas which was the specific intent of it.
A few years ago, there were hundreds if not thousands of efforts to keep Christmas out of any public square in any way. Trump has openly pushed back on that effort. That is what she is talking about.