Is it a sort of 'texting' shorthand? The "Cross" followed by "tian"? Otherwise it reads as Ex-tian which makes no sense in context .
Shorthand it might be, and one sees 'Xmas' instead of "Christmas' here in the US; some even say it like that; 'ex-muss'.
Some evangelical Christians take offense at this and see it as a diabolical attempt to remove the word 'Christ' from both terms. I'm not quite so wrapped around the axle about it. I would just prefer to see the correct term used.
Unless we're talking about the English, whom I take devilish delight in mistreating.