Now you are being silly. Its done because Jules did it. C'mon be honest - nothing to be ashamed of.
To be honest I've spelled Christmas as Xmas for 30+ years. I do it because my grandfather (a lay preacher) did. I spell Christian as Xtian to annoy ;-)
'Fraid not Peter. Many of the occult and pagan mags from the '80s were writing "xtian", from where I presume Julian himself got it.