Christmas has always been a celebration of mid winter ( more specifically the winter solstice in the northern hemisphere,) as far back as records go there has always been some variety of taking a evergreen tree as a symbol of the return of the sun. Red might be part of the evergreens berries (holly), but mostly it’s because coca cola advertised with a picture of St Nicklaus dressed in their corporate colours, instead of the traditional green.
Welcome to being older. The magic goes and the cynisism sets in. There is still hope though. If you can clear your eyes of the razzle dazzle of unfettered consumerism, you can realise it’s a nice time to spend with those you care about. Makes it an even better time of the year. Edit. I realise that sounds too flippantly jolly. My point was that for all of human history this has been a festival to stave off the deprivations of starving and freezing. I just feel this< angle is a good way to look at it.