Use of the term perpetuates the Black Legend. Words count--pro-choice rather than pro-abortion has permitted abortion to gain a foothold it might never have had had the manipulators not won that media battle. When a Catholic uses "Bloody Mary" he contributes to the perpetuation of anti-Catholic prejudice. I'm sure it was not intentional, but it's effect is the same. :)
What's wrong with "Bloody Mary"? That moniker commands respect.