Islam is the immediate threat...
The Lutherans and Calvinists weren’t out to annihilate the Catholics back then...
TULIP wont kill you but the sword will...
Here is wisdom!
During the course of the Thirty Years' War, the population of western and central Europe was reduced, by some estimates, by 50% or more. Regions of Germany and Czechoslovakia saw 3/4 of the population lost to war, famine, and disease. Many small locales experienced total annihilation.
It's worth noting, with the intertwining of state politics and religion, that Lutherans and Calvinists and Anabaptists slaughtered each other as well at times. Swedish troops put entire Catholic populations to the sword, and when they moved on Imperial troops swung by to wipe out Protestants. Unpaid mercenaries came through afterwards to wipe out anyone who happened to survive.
Suffice to say, everyone was out to annihilate everyone else "back then". Islam is still "back then".