It's a bigoted title used to demean, humiliate and insult Christians. It's like saying "******" instead of black.
It's like Xmas. Care4All says there is nothing wrong with it. IMO, anything that makes typing easier is cool.
Always A Bitch takes offense to it because she can't allow thoughts about anything outside of her own little narrow views. "x" basically means "whatever", and the "tians" is a reference to theologically challenged people like Always Babbling.
Actually the Jews started doing it many years ago. They wanted to sell Christmas items out of their stores, but didn't want to write Christmas on their windows. So to eliminate the word Christ. They would spell it Xmas