"The "Religious Wars" of the 16th and 17th Centuries (I include the Thirty Years War) involved millions and millions of deaths, mostly of the innocent."
No argument there. But there was also political impetus to the battles credited to religious differences. Theology wasn't all, maybe not even most, of what set the Swedes into Germany. Richeleu was Catholic (but French first?).
"~ even built this drowning machine. This got rid of them; ~ stupidity of the Revolutionaries."
Yes, the revolution tends to eat its own, in addition to many others.
"When you are doing a genealogical search . . ."
Yes, you have to learn about history, too. My French ancestors were Catholic rather than Huguenot; I found them, but boy did Napoleon's date system cause me grief. (I am trying fill in the dots for some who were prob. Anabaptists from Switzerland.)
I read of the Prussian Huguenots in an autobio. of Fred. the Great, and in Guenter Grass' Too Far Afield.
Regrding the Third-Years-War, when we get to the Danish phase, it's definitely a religious war, but one that seems to be between the Lutherans and the Presbyterians!
With 98% of the folks in Scanderhoovia and environs being at least nominally members of the Lutheran state religion, it kind of looks like the Presbyterians "lost" ~ must be why they all moved here, eh?!
Regarding Richilieu, his Grandfather or (Great Grandfather depending on the record you look at) Champigny was the youngest son of a Huguenot noble family (even had Bourbon, Valois, and other well-known relatives). Once Richilieu got a chance he stole Grandpa Champigny's estate for himself. Richilieu stole many other properties from his relatives.
Of course, he was just the sort of fellow who would have done that even if they weren't his relatives, and without respect to anyone's religion. We call people like this "opportunity thieves".