Why do we refer to Christmas as Xmas now?

Anyone know why there has been a incremental move towards the use of the word "Xmas" instead of "Christmas" in every day life?

Here's a supposed reason, but I don't buy it;

[link to www.grammarly.com]

IMO it looks like there's been a shift away Jesus towards something more sinister, even if it's just an X. Why does an "X" replace "Christ" if it's a celebration of Jesus' birth and not his death? Also, why the need to shorten the word in the first place?

Most people don't realise these subtle changes, but I reckon it's another shift away from celebrating the life of Jesus with pagan imagery. We already have Santa (satan), which is pagan depiction of Chronos the god of time and Saturn. God is also depicted these days as a man with a white beard.