I allways find happy holidays or the over corrections to appease other holidays that are irrelevant to those communities to be bizzare and weird. No one celebrating Hanukkah, Kwanza (so miniscule), is ever really offended by merry Christmas. And I would say the same if Ramadan was on same exact time as Christmas.
So dont try to put on silly point of views I didnt express on to me. But its a historical fact that on the core Christmas has little to nothing to do with Christianity. It got adopted around the religion because it became the dominant religion, but the traditions, the mysticism and mythology of the feast itself ALL predate Christianity.
Humans aren't that complicated, like everything else they borrow and re shape their traditions. Its not the same celebration, but its super obvious to acknowledge the origins. Christmas has fully evolved from pagan feasts, down to date and customs . Wether its saturnalia that has very little in common with current Christmas traditions (except the date itself, 25th) , or the more closely resemblances of North European pagan winter solstice traditions that Xmas literally borrowed from, from customs down to the actual name of the holiday in many of these countries (im not kidding, Swedens name for Xmas is same as the pagan holiday), down to the very myth of Santa Claus, or later Father Christmas, who you hardly can call a Christian entity, but simply a reshaped old tales, a cocktail of many versions of magical gift giver in pagan times.
To make it clearer. There is not a single mention of Christmas in the bible, not a single one.
It simply a tradition that was born of needed and clever pragmatics in earliest Church days. Emperor Constantine was smart enough to know that you convert or beat pagan religions not by force alone, but by directly taking their traditions away. So he gave his new converts a rebranding of something they are familiar with. And it evolved from there for centuries.
The church at the time said its the birth of christ, even tho no one knows (there's no fact about his birth year let alone month or day) to nail the tradition down, and its a wonderful and beautiful thing to celebrate with family for sure. But at its very core, there's nothing truly Christian or relating to Christianity with Christmas. Atleast when it comes to the mainstream branches of Christianity. With Orthodox/coptic ones, its fully and completely religious event. They don't mess around.
Its also why I said Easter is the main bona-fide christian holiday.