We are one people. The slaughtering was a two way street & as was pointed out earlier, one must put actions into context of their historic times.
What gave the Catholic Church a rightful claim to ownership of the properties "stolen" by those who chose to remove themselves from the power of Rome? Did they not have any claim to the property, as it had been their ancestors who had "donated" it?
"What gave the Catholic Church a rightful claim to ownership of the properties "stolen" by those who chose to remove themselves from the power of Rome?"
The Catholic Church had nothing more than MORAL AUTHORITY over the European monarchs. The Church was influential insofar as it lent legitimacy to the various secular regimes that were in existence. At that time, the radical protestant Kings or Queens demanded COMPLETE OBEISANCE from their "subjects", including the Catholic members within their realms. If the Catholics under their charge complained about royal abuses, as the English and German Catholics did when their monarchs were involved in Machiavellian courtly and political intrigues, they were MERCILESSLY SLAUGHTERED.
"Did they not have any claim to the property, as it had been their ancestors who had "donated" it?"
To enlarge the royal purses of the monarchs in protestant countries, the property that belonged to the CATHOLIC COMMUNITY (not just the "Church", as you say) was confiscated and STOLEN to enrich themselves.
The same thing is happening TODAY within the Anglican community. Those members of the Anglican Church who don't agree with heretical practices (gay marriage, female and gay bishops, etc.) who want to protest are forced to deal with the fact that THEIR PROPERTY is being held hostage by apostates in the Anglican hierarchy. It is ironic, indeed, to watch this happen to the very people who originally STOLE what they have from Catholics in the first place.