I dispute that the Westboro "Baptist" "Church" folks are Christian at all.
But stipulating, ad arguendo, that they are ...
The answer is "zero". The Westboro "Extremist Christians" have killed zero people. Extremist mohammedans have killed infinitely more than they have.
That’s my point....let’s just assume for the sake of argument that the Westboro folks are Christians.....the fact is, they still have killed fewer people than Ted Kennedy’s car.