It isn't a "myth" , it's simply a way of describing his nationality because the area is now in modern day Turkey.
It's also more usefully inflammatory, especially when debating about him with Little Englanders.
All well and good, but we've never really "celebrated" St. George's day in this country not in the way other countries do.
The Church of England is very big on the whole saint thing (unlike the Catholic Church) and particularly not this one. It's historically had an issue with a mythical...