Not every site that claims to be sharing Catholic teaching actually is. These people are putting forward their own opinions about what ought to happen to heretics, not what the Church teaches. I’d ignore them.
The Catholic Church never claimed this right. It handed heretics over to the secular authority to be punished according to the laws of the State. They could also do this with other serious offenses against the Church that were also offenses against the State. One might wish, for instance, that the Catholic Church had followed this route more readily with priests who sexually abused minors. That was a case where the Inquisition would have been a really good idea!
Here’s another case that illustrates why this Church-State collaboration might not be so horrible (though not, IMHO, with the death penalty as the final result and not for every case of heresy). I heard this morning on the BBC about a pastor in London who allegedly denounces children in his congregation as witches and publicly prays that they will die. There have been cases of horrible violence against children in this congregation and the BBC understandably blames the pastor. They are outraged that the government can’t step in (because calling someone a witch or praying against them is not an offense under British law, and they can’t prove that the pastor actually encouraged physical violence). But of course the problem is that the BBC is working from a secular point of view that assumes that there is no such thing as the demonic. They pointed out (obviously as a slam against Christianity in general) that more “mainstream” Christian churches such as the Anglicans and the Catholics also allow for exorcism. Of course, they ignored the important theological distinctions between orthodox theology and what this guy was doing (because they probably see no real difference).
I was listening to this and thinking, “you know, England does have an Established Church and it would come in handy right about now, if it had any real power.” This is what an established church is for–not to coerce people into accepting one particular religious perspective, but to provide a standard of what is and is not a socially acceptible form of religion. The plain fact is that there is no meaningful “neutral” standard to invoke in a case like this. Either demons are real or they aren’t. To brand all exorcism as abusive (think of the real-life case behind the movie The Exorcism of Emily Rose) is to impose secularism. But to say that churches can do whatever they like is to allow for horrible abuse. A state church with teeth would have the power to say “sorry, pastor so-and-so, but you have no right to do this to children in your congregation, and if you keep doing it we will proclaim you a heretic and hand you over to the civil authorities for punishment” (not death–I am not defending the death penalty here).
I know this is going to sound very strange to American ears, or modern Western ears in general. But this story on the BBC really made me think about our facile condemnations of secular penalties for heresy. That was what the BBC was calling for, whether it admitted it or not.
Something you have to remember is that in the Middle Ages, you did not have the pluralistic society we have today. There was only one church, the Catholic Church, and as a result, heresies not only affected the Church, but civil society as well. The Albigensian heresy was a prime example. They were basically recycled Manicheans, who believed in a “bad god” of the Old Testament who created matter, and a “good god” of the New Testament. They considered marriage and having children as sinful, thought fornication was ok, and considered ritual suicide a virtue. They were not much different than today’s culture of death. These teaching threatened not just the church, but the very fabric of civil society as well, which was why the church and state came down hard on them.