Biting the Hand that Excommunicated You

Today is the anniversary of the martyrdom of Stanislaus of Cracow, patron of Poland. On this date in 1079 (only a century or so after the Poles converted to Christianity, to give you some context) he was killed while celebrating Mass by the aptly named King Boleslaus the Cruel, whom Stanislaus had excommunicated for various reasons (pillaging in his wars with the neighboring powers, attempts to seize Church land, the kidnapping of a nobleman's wife). (He's sort of the Polish Thomas a Becket, then.)

That's a Medieval phenomenon I just don't comprehend. I mean, I understand being upset about being excommunicated. I just don't see how hacking to death the one who excommunicated you is an appropriate response. If you're a believer, and are worried you're now Hell-bound, it doesn't get you one bit closer back to integration with the Body of Christ. (God, I think, remains unimpressed by your slaughtering abilities.) And if you're not a believer, then who cares? Despite the excommunication, people are still going to deal with you, because you're rich and powerful (it's never excommunicated hog-farmers who go after the clerics, notice). Maybe I'm just too solution-oriented. I love the Medievals, but they really could be a maddeningly adolescent bunch, sometimes.