The "trouser thread"? lol Sounds like one of those political scandals or something. "Trousergate!"
Ok, but on topic, was it all right to burn heretics? Well, there may have been a more 'humane' way to do away with them but... perhaps not a more symbolic? Anyhow, the concept of removing someone from this life who poses a serious threat to the fabric of all that is good and just in this world is pretty rational. Just like condemning error and not allowing it equal rights with truth is pretty rational.
Some things in life are necessary, even if unpleasant. (Except perhaps the infamous trouser thread.)
This is also along the same lines as questioning the inquisition, I might add. One must wonder just how many heretics actually were burnt at the stake. I have learned in the last some years, for example, that the history of the crusades and inquisition have come to be portrayed under a very, very false light. It's an interesting topic. Makes one wonder how much of history in general we've all swallowed that was in fact totally off.